Former Gardens Manager Andrew Smith took it upon himself to make a record of notable plants in the Gardens over a period of two years. Scroll down to see what was happening in the gardens…..
Andrew’s Plant of the Week…….28.04.22: Brachychiton rupestris
This week I’m featuring my favourite individual tree in the Gardens, the large Brachychiton rupestris, on the south-eastern end of the Native Garden. From a conversation I had with Geoff Olive (staff member at Burnley from 1967-1999), before he died in 2016, I gather that this Queensland Bottle Tree was transplanted into its current position in 1962, the first year Geoff began studying at Burnley. Although we don’t know the exact size or age of the tree when it was transplanted (it took two men to transplant it), it is likely to be at least 65 years old.
The natural range of Brachychiton rupestris is from central Queensland down to northern New South Wales, on a range of soil types, which makes it very adaptable to planting outside its semi-arid environment. The species has an amazing ability to be successfully transplanted, even when mature, with the bonus that it can survive months out of the ground before being transplanted, so can be transported long distances, all of which has combined to make this species well known and planted all over the world. The most often used common name, Queensland Bottle Tree, is of course named for the characteristic rotund shape of the trunk, which can easily reach two metres in diameter when mature. While they are known in their native habitat to reach a height of 18-20 metres, in cultivation they are more often seen at half that height. The swollen trunk is in effect a large water storage vessel, that can sustain not only itself in times of water deprivation but also humans and animals who are canny enough to dig into the bark and tap into the water reservoir held between the inner bark and the trunk.
The large specimen we have at Burnley has been periodically affected by Phytophthora cinnamomi (Cinnamon Fungus), and so far, the occasional intervention with fungicides and soil flora tonics has enabled it to battle on regardless. The Bottle Tree, like many species of the genus, tends to drop its leaves prior to flowering in late spring to early summer, and in the case of our tree, half the leaves of the canopy, on the northern side, tend to fall off, giving the impression of some horrible health problem*. The leaf drop prior to flowering is a common response for numerous Australian plant species in northern Australia, where summer monsoon rains is the predominant rainfall pattern.
The small flowers of the Bottle Tree need to be closely inspected to see their full beauty, with a large colour range possible between individual specimens, ranging from greenish white to pink, as well as striped petals.
The large specimen in the Native Garden was one of the first trees in the Gardens that I felt needed a replacement specimen, with the 1990s Phytophthora problem and its slow growth rate prompting me to plant another young seedling on the nearby boundary fence line. This young tree came from our own nursery, where it and numerous other seed grown specimens had been propagated. Although I don’t have an exact planting date for this replacement tree, it was around 1990-1992, and as you can see in the photo, hasn’t, as yet developed a rotund trunk to match the old timer next to it. I’ve also, in 2021, planted a third specimen near the other two, this time a grafted specimen from David Bearsell, with the scion material (the vegetative top section that is grafted onto a Brachychiton rupestris rootstock) taken from the specimen at the entrance to the Geelong Botanic Gardens, which has an outstanding trunk and habit.
With these three specimens planted roughly thirty years apart, a long term Bottle Tree display is ensured for many decades to come, and given how slowly they grow and develop, without this planning for the future, the characteristic trunk would not be a feature for future students and visitors to admire.
* Its nearby cousin Brachychiton discolor has the same pattern of annual leaf loss.
NOTE: As many of you will know by now, Andrew has retired from his position looking after the Burnley gardens, so this might be his last Plant of the Week for a while. But never say never. He may send one or two as time goes by. We will see.
Andrew’s Plant of the Week…….04.03.22: Nerium oleander ‘Madonna Grandiflora’
This week I’m featuring the well-known evergreen shrub, Nerium oleander, or as its commonly called, Oleander. There are numerous cultivars of this large shrub; the one I’m highlighting is the semi double white flowering ‘Madonna Grandiflora’. We have this growing as a high hedge on the Eastern Drive roadway above the quadrangle area, and as it’s next to the pedestrian pathway, the delightful fragrance is easily detected. I noticed recently that the high humidity we have been experiencing increased the fragrance dramatically, to make it even more impressive as you walk past.
This three-metre-high shrub is cut back by about a third, or sometimes more, each year, in early spring, to produce numerous new stems that flower several months later. The flowering period is reasonably long, several months at a minimum, and even now in early autumn it is still producing new flowers. The shiny, long green foliage is very luscious-looking, a bit longer than other Oleander cultivars, so the overall affect of the dense shrub is of a clean-looking, dense, informal ornamental hedge. Of course, an individual specimen can also create a fantastic feature plant, as the rounded shape makes a great form for gardens.
The genus Nerium has a high aridity tolerance, and is used all over the world in non-irrigated, hot, dry climates, as a dependable, colourful shrub for all sorts of situations, such as in the median strip of freeways in central and southern Spain. The hedge we have next to the roadway isn’t irrigated and even in the height of summer, with extreme high temperatures, the foliage never seems to wilt, and while the white flowers do tend to brown off, there are always plenty of flowers in bud that soon open up and prolong the floral display.
Andrew’s Plant of the Week…….04.03.22: Lagerstroemia indica
This week I’m featuring a flowering tree, the Crepe Myrtle, which I’m sure you have all admired over the last few weeks in your neighbourhood or in the Gardens. Burnley has several cultivars of Lagerstroemia indica, including the smaller ‘Nana’ form and the low growing ground cover ‘New Orleans’. The Gardens also has other Lagerstroemia, the earlier flowering Lagerstroemia fauriei ‘Fantasy’ and the well- known white flowering ‘Natchez’. There is a wide range of cultivar colours for Lagerstroemia indica, from red, to purple, mauve, and pinks, both soft and hot pinks – a fantastic colour choice for all tastes.
l-r Lagerstroemia indica ‘Nana’, Magenta form, pale pink form, Lagerstroemia indica ‘New Orleans’
Because they flower in late summer and autumn, on last season’s Spring growth, Crepe Myrtles can be pruned heavily during winter, once established, to promote multiple stems for an increased flowering display. Often, heavy pruning of trees doesn’t improve form or flower potential, but in the case of Lagerstroemia, it can dramatically increase the floral display at a time of the year when most plants are struggling to cope with hot seasonal conditions. The medium to high aridity tolerance of this genus also makes it suitable for low or no irrigation situations, and while the foliage of unirrigated trees will wilt, the flowers still hold up well in water deprived soils.
Andrew’s Plant of the Week…….25.02.22: Punica granatum ‘Nana Plena’
This week I’m featuring one of Burnley’s older shrubs, the double flowered Dwarf Pomegranate, Punica granatum ‘Nana Plena’. This deciduous 1.5-metre-high shrub was planted in the early 1930s, as part of the planting for the rockery opposite Reception. The rockery is named after Hilda Kirkhope, a lecturer at Burnley during the 1930s, who designed this west facing bed and supervised the students who built and planted it up. The 3-metre-high rock embankment was conceived to hide the fenced enclosure where the resident bull was kept (part of the dairy herd that was at Burnley for 50 years), and also, as the bed was at the entrance gate to the College, to improve the visual appeal of entering into the Gardens and Pavilion building where the teaching took place. Rockeries were of course very fashionable in the 19th and 20th centuries, as they were a way to improve the growing conditions for plants, such as providing better drainage.* In typical Burnley fashion of creating something from limited resources, the rocks for the rockery were likely procured gratis from a nearby park, and student labour was used to do the rest. The Yarra Boulevard would have been completed around the same time as the building of the rockery, which would have made it quicker and easier to transport the rocks to the site.
There are several forms of the Dwarf Pomegranate. The original cultivar was a chance seedling (‘Nana’), first described in 1803, which has single flowers, thorns, and small, sour but edible fruit. The double-flowered cultivar we have doesn’t produce any fruit and is thornless, but displays all the other desirable traits of this compact shrub, with bronze coloured, new spring foliage, bright orange flowers, ornamental, butter-yellow autumn foliage, and suitability for semi-arid conditions (once established). Additional irrigation during summer will increase the quantity of flowers produced, with flowering continuing into autumn.
* There might have been some influence from England, where it was fashionable to construct rockeries for the then treasured alpine plants. – Ed.
Andrew’s Plant of the Week…….16.02.22: Ceratostigma plumbaginoides
This week I’m featuring one of my favourite ground cover plants, the often admired Ceratostigma plumbaginoides. This plant has a few common names; perhaps the most confusing one being Plumbago (which was an earlier name for the genus), as I always think of the well known, related genus Plumbago, that also has late summer and autumn flowers. The word plumbago comes from the Latin name “looks like lead” and was first used over 2000 years ago. Another curious common name is Leadwort, which has several lead-associations including that the flower resembled the colour of lead (I thought lead was grey?), that it cured lead poisoning (unsubstantiated) and that it was used to make a lead staining plant dye (possible). There are other plant genera that include Leadwort in their common names, so perhaps Chinese Plumbago is the best of the bunch, as the plant does originate from China. The first European sighting of this plant in China was in 1819, when an English gardener, Clarke Abel (Abelia was named after him) visited the Imperial Court in Beijing, and noticed it growing in pots. It was more than a decade later in 1833 before it was collected and botanically described, and from there, like so many plants and cultural items from China and Japan during the 19 Century, it was then distributed all over the western world. There are eight species of Ceratostigma; the Gardens have four of them, including the most common one, C. willmottianum. The genus is a mixture of evergreen and deciduous, or partially deciduous plants, depending on the regional winter temperature extremes where it is grown.
The autumn colour of Ceratostigma plumbaginoides is reasonably good, more bronze-red than the striking red-scarlet of C. willmottianum, but still impressive in its colour, and the length of time the colourful foliage persists on the wiry stems. The native habitat of Ceratostigma plumbaginoides is in low, rocky hills in north western China, around Beijing, so this gives you a good indication on the plants ability to survive the extreme climatic conditions of low winter temperatures and periods of water deprivation in summer. I consider C. plumbaginoides to have one of the highest aridity ratings of any plant. It grows in situations where normally very few species can grow, in full sun and full shade, and unlike many plants that grow in both light situations, still flowers well in shaded situations. The only drawback of this species is its underground suckering, which means it will spread throughout the bed where it is planted, even growing in cracks between walls. I don’t consider this trait to be a problem, as it seems to co-exist with other shrubs and grasses and doesn’t smother or impede its plant neighbours. The flowering period is continuous from early summer until late autumn and the only maintenance needed is a close cut down to ground level with hedge shears in late winter, when the last of the autumn foliage disappears and the wiry stems might give the impression of neglect. The re-growth in spring is delayed, so it’s possible to grow low spring bulbs in the same bed, to avoid the area looking totally dormant.
P.S Plant with caution/ Ceratostigma plumbaginoides is indeed a charming, tough plant, but once you have it, you will always have it. The tough underground stems snap off, and regrow if you try to weed them out. Ed.
Andrew’s Plant of the Week…….11.02.22: Clerodendrum trichotomum
This week I’m featuring a plant from the genus Clerodendrum, with which you are probably familiar, although the species trichotomum may be less well known. This large shrub or small tree is growing in the North Island Bed, on the east side of the Main Building, and at this time of year has delightful, fragrant white flowers to catch your attention. This deciduous plant is widely dispersed throughout eastern Asia and India to the Philippines. It has a few common names, one of which, Harlequin Glorybower, describes the appearance of the fruit (a drupe, surrounded by a persistent calyx), and another, Peanut Butter Tree, which refers to the odour of the leaves when crushed. The flowers begin in late summer and continue into autumn, with the curious transformation of the green calyces into red, five-cornered stars that hold a single, central, jewel-like drupe, that starts off white and slowly changes colour to bright blue. It is this multi-colour mix of bright colours, happening all at the same time on different parts of the branches that gives rise to the reference to a harlequin in the common name. The autumn foliage colour is nothing special and its habit is described by several sources as being ‘unkempt’, a rather untidy attribute to saddle a plant with, but perhaps initial pruning can improve its form, as our specimen has a single lower trunk with upper, well-spaced branches, so doesn’t strike me as deserving of such a derogatory name.
Although renowned for its suckering habit (like some other Clerodendrum species), our specimen has only produced a few outlying protégées, well away from the original plant, so perhaps soil disturbance by cutting the root system can cause suckering to occur. Certainly, in its native habitat, it is known to create dense thickets and is planted as a hedge or to create a copse (plants growing close together).
Andrew’s Plant of the Week…….05.02.22: Brachychiton discolor
This week I’m featuring one of our large older trees in the Gardens, the Queensland Lacebark, Brachychiton discolor. This tree, as its common name suggests, has a habitat range from central NSW up to Mackay in Central Queensland (with an additional reported small population in far north Queensland), where it grows in a range of habitats, mostly dry or moist rainforests. Commonly seen in landscapes well outside its natural range, this tree has a reputation for having a compact root system, so is ideally suited as a street tree, or in situations with confined root volumes, such as next to buildings. Like other well-known Brachychiton species, such as the Illawarra Flame Tree (B. acerifolius) and Bottle Tree (B. rupestris), the Queensland Lacebark tends to drop its leaves prior to or during the flowering season in summer, in response to the reduced rainfall conditions of their natural habitat. As is often seen in other Brachychiton species, our specimen at the western end of the Rainforest Garden at Burnley will typically only lose part of its foliage, with some branches remaining fully covered with foliage and others completely bare and covered instead in a mass of flowers. It is this summer deciduous habit that makes the flower display so prominent, with the flowers easily seen at great distances and the carpet of intact flowers that fall underneath the tree also making a marvellous colourful display. As you can see in the photo, the outside of the flowers are quite textured, and while the flowers of our Rainforest specimen are a dark pink, our other large specimen along Eastern Drive has much paler pink flowers; there is a considerable variation in flower colour within the species. This Brachychiton hybridises freely with other Brachychiton species such as B. acerifolius; the resulting hybrids vary in foliage, trunk and flower colour. I left a self-sown specimen in a Native Garden bed adjacent to Rainforest, and the hybridised mix of the Illawarra Flame Tree and Queensland Lacebark is very evident, with the Flame Tree traits of green trunk and smooth foliage dominating but the pink flower colour of the Queensland Lacebark persisting.
The tree growing on the western end of the Rainforest Garden has been given a planting date somewhere between 1910 and 1930, the same time period in which two other Australian trees, Alectryon subcinereus (Native Quince) and variegated Pittosporum undulatum were also planted quite close by. These trees are thought to represent the first time a collection of Australian plants were planted together in a bed, rather than combining species from different parts of the world. The planting is thought to have been a response to Australia’s Federation and the rise in Nationalism of the time. It was not until Ellis Stones, in his Rock Outcrop garden outside the nursery, in the early 1960s, once again only used Australian plants in a Burnley planting design.
Andrew’s Plant of the Week…….26.01.22: Nymphoides geminata
This week, to try and make you feel a bit cooler in this hot weather, I thought I’d feature another water plant, Nymphoides geminata, with the common name of Marshwort, or Entire Marshwort. We have this small-leaved aquatic perennial/annual growing in the Native Garden Ponds and streams, where it either floats on the surface of the water or grows on the saturated edges. That’s the great thing about this plant, it doesn’t need to grow in the water, it can easily thrive on the margins as well.
This well-known plant was first described in 1810 and has a wide geographic range, from New Guinea, down all the Eastern Australia states, and into South Australia as well, where apparently it’s considered an annual. The circular leaves of the Marshwort are a lovely, shiny, bright green colour, and if growing in water, are either held up above the surface or float on top. It grows in streams and ponds, usually less than one metre deep, and the leaves are stable enough to support small frogs and other water-loving creatures. The beautiful, 3 cm, bright yellow flowers have a long season, from spring through to autumn, and are held 5 cm above the foliage, on stout little stems (pedicels), so well displayed and easily noticed. It is the fringed margins of the petals that attract your attention the most, a feature of most Nymphoides species, rather than the entire margins of the flowers of other water plants.
This is another plant that can be grown in a pot with no drainage, or in a small water tub, if you can control the mozzies. It will tolerate a wide range of light conditions but will flower better with sunlight, and if the soil completely dries out, it will set seed and germinate when wetter soil conditions return.
Andrew’s Plant of the Week…….19.01.22: Lythrum salicaria
This week I’ve chosen another plant that is growing in the Luffmann Lily Ponds, Lythrum salicaria or Purple Loosestrife. This is a well-known plant from Europe, Asia and North America, as well as the east coast of Australia, often seen growing in damp or periodically wet areas near water, and in some regions of the world is considered a weed. We’ve planted our specimens on the islands in the ponds and although it is known to spread by seed, the only spread we get is by the clump vegetatively slowly growing bigger each year.
One of the best things about this long lived, mid-summer and autumn flowering species is its long flowering period. Initially it flowers on terminal spikes, and then the flowering period is extended as the side laterals on the stems also develop flower buds (even if they are a bit smaller than the earlier, larger terminal flower spikes). This perennial has many fine qualities, including good, red autumn foliage, and stout, self- supporting, woody stems that don’t have any trouble keeping upright in strong winds, and therefore need no support. It also has the remarkable feature of not dying out in the center of the clump as it ages, and its spreading rhizomes aren’t rampant, so it doesn’t need dividing and replanting to stop its encroachment, or to fill in gaps in the clumps.
In this hot summer month, when we are often a slave to hand-watering of pots or garden beds, this perennial can be grown in a container without drainage, and topped up with water as needed, and unlike some other plants that grow on the edge of water, won’t completely die if water isn’t available for an extended period.
Once the red autumn foliage has finished, the chunky stems are cut down to ground level, from where, like all herbaceous perennials, it will then regrow quickly in spring, and if given enough moisture, grow up to 2 metres in height. The January and February months are always less floriferous in general, compared to the earlier spring and early summer period, so this repeat-flowering perennial that copes well with high temperatures (provided moisture is available) is a great inclusion…provided you like pink. It’s interesting that Lythrum is related to Crepe Myrtle, Lagerstroemia (in the same family, Lythraceae) which is also a star flowering performer in the hot months of mid to late summer.
Andrew’s Plant of the Week…….12.01.22: Geranium ‘Gerwat’ ROZANNE
Andrew tells us “This Week I feature the plant that won The Royal Horticultural Society (RHS) ‘Plant of the Centenary’ at the Chelsea Flower Show in 2013, Geranium ‘Gerwat’. This Cranesbill is more commonly known under its trade name ROZANNE. To celebrate the centenary of the famous Chelsea Flower Show, the RHS selected 10 plants that had been launched at the Show since 1913, one to represent each decade. Some of the other well-known contenders that were voted on by the public included Pieris formosa var. forrestii (Japanese Pieris, 1923-32), Lupinus Russell hybrids (Russell Lupins, 1933-42), Rosa ‘Iceberg’ (1953-62) and Erysimum ‘Bowles Mauve’ (Wallflower, 1973-82). It’s not hard to see why ROZANNE (1993-2002) was chosen as the winner, as this herbaceous perennial is smothered in superlatives when people refer to it. Some of the words you will find used to describe this hybrid include: “unsurpassed”, “excellent garden plant”, “exceptional”, “long lasting performance”, “unique”, “lives up to its reputation”. As well as being winner of the 2013 ‘Plant of the Centenary’, other awards include the 2006 RHS Award of Garden Merit, and the 2008 RHS Plant of the Year. Perhaps the only two flaws I can see are that it virtually disappears in winter, and that it requires irrigation to stay alive during summer in Melbourne.
So, why all the high praise? The most brilliant feature of this geranium is the long flowering period, essentially from spring right through to autumn, about 8 months. The large, vibrant, violet-blue flowers have ornamental purple-violet veined petals, and a white centre, and are well displayed above the foliage; like many geraniums, they are abundant and prolific. Next, we have the foliage, which is ornamental even without the flowers, and is deeply divided, with a slight yellow-green marbling and prominent venation. The final great attribute of this geranium is the fast growth habit and high heat tolerance; even a 38-degree summer day doesn’t scorch the foliage. You can expect much larger individual blooms in the first few months after winter dormancy is over, with the flowers becoming smaller as summer heat sets in, however, the number of flowers isn’t reduced, just the size of individual flowers.
This hybrid appeared as a chance seedling in a Somerset (UK) garden in 1989, where numerous other geraniums were being grown, and is a cross between Geranium himalayense and Geranium wallichianum ‘Buxton’s Variety’. The owners of the garden, Donald and Rozanne Waterer, recognising its outstanding qualities, contacted Graham Thomas (rose breeder and author of the classic Perennial Garden Plants) who put them in contact with Adrian Bloom of Blooms of Bressingham, the perennial plant producers, who introduced it at the 2000 Chelsea show. It was then propagated, patented in the UK and US, and sold all over the world under the trade name of ROZANNE, after Mrs Waterer, who was the geranium enthusiast in the couple’s garden. The US and UK patent expired after 20 years in February 2019. In Australia, PBR (Plant Breeders Rights) was granted in 2003, and will expire on 25 September 2023. Despite being widely known as ROZANNE, the registered cultivar name of the plant is ‘Gerwat’, which is derived from Geranium and Waterer. The two names have caused some confusion, and you will find numerous variations on the internet, such as Geranium ‘Gerwat’ ROZANNE, Geranium x gerwat, GERANIUM x ROZANNE® ‘Gerwat’, Geranium x ‘Rozanne’ (Gerwat), Geranium ‘Rozanne’, and Geranium ROZANNE ‘Gerwat’! A geranium by any other name…”
Andrew’s Plant of the Week…….22.12.21: Pontederia cordata
This week I feature one of the water plants growing in the Luffmann lily ponds, Pontederia cordata, that has the common name of Pickerel Weed. As the common name suggests, this water plant will vegetatively reproduce rapidly, and like most water plants, will eventually take over the entire pond if left to grow unimpeded.
The flowers are numerous and long- lasting, with a succession of flowers being produced over the summer months. The light green, arrow shaped foliage, held vertically above the water, dies back in late autumn, when we cut the stems down below the water line, to then re-emerge in spring.
Pontederia cordata has excellent water filtering abilities and seems to do a good job of keeping the water in the shallow lily ponds clear and healthy.
This plant could also be grown in a non-draining, saturated pot, in or out of the water and provided ample moisture is available, will thrive in full sun conditions.
Andrew’s Plant of the Week…….16.12.21: Themeda avenacea
This week I’m featuring a native grass, and while you will all be very familiar with Kangaroo Grass (Themeda triandra), you probably aren’t as familiar with the lesser-known Oat Kangaroo-grass, Themeda avenacea, a taller species that is currently looking impressive in the Gardens.
This 1.5-2 metre high grass grows in all Australian mainland states, where its natural habitat is inland floodplains and natural depressions, on fertile soils. Burnley lecturer Chris Williams was given some seed by his brother, from his farm in north-western New South Wales, and the plants Chris grew immediately impressed me with their tall, graceful seed heads. The bed where the seedlings were planted in 2016 is in the lagoon paddock, the grass area adjacent to the Yarra river, between Swan Street and the Library, and the clumping grass forms the central rib of vegetation in the narrow bed. This serpentine bed was created in 2015 to delineate the campus boundary, after campus Head Stefan Arndt suggested the chain mesh fence be removed to make the Campus seem more accessible and open to visitors.
The purple seed heads of this Themeda species are held aloft on tall, robust culms (stalks), and sway gracefully in the wind, so provide both colour and movement as you walk by. The stout culms remain intact throughout summer and autumn, and it is only when the cooler, wetter weather sets in that we cut them down, level with the top of the foliage, so they don’t look unkempt. Cutting down the foliage to 10-15cm above ground level is left until early spring, as no vigorous regrowth occurs in the winter months.
This grass has proved to self-sow freely, too freely for the adjoining shrubs and Wahlenbergia species either side of the grass clumps to cope with, so an annual seedling removal is needed in springtime to curtail its spread. Like most grasses of the world, this Oat Kangaroo-grass will take over and dominate, if given enough sunlight and opportunity. The long linear bed is un-irrigated, so you can consider this Themeda species to be suitable for low rainfall areas, however, root competition from trees reduces its height and vigour, as does shade, the impacts of both are evident from the stunted growth of the grass clumps along sections of the bed where trees are growing.
Andrew’s Plant of the Week…….8.12.21: Trachelospermum jasminoides
This week I’m highlighting another well- known plant, and one of my favourites, Trachelospermum jasminoides, the Star Jasmine. We have this plant growing in several locations in the Gardens, used both as a climber on a fence, and as a ground cover. That’s the great functionality of this plant: it can either be a vertical or horizontal specimen, or even grown as a mounded plant in a pot, in its early stages of development.
There is a great deal to admire about this plant, which is why it’s so popular. For a start, the dark green foliage is handsome enough to grow in its own right. Then when you add masses of well displayed, fragrant white flowers, that are produced for several months in the warmer months either side of Christmas, this plant really starts to pique your interest. One of the reasons for its popularity is its adaptability to different types of soil, both in terms of soil pH and type, as well as its adaptability to different sunlight levels, from full sun to full shade, so no matter what your site situation is, this plant will perform consistently well.
There are very few climbers that I consider suitable to entirely cover a wall or structure from top to bottom, as the majority end up with the lower section bare without any foliage cover. The Star Jasmine, even in shaded sites, can grow and maintain full foliage cover from the bottom, right up to the top of the wall or structure, a great trait for a climber to have.
Perhaps its use as a ground cover is where this plant is most surprisingly useful, as it has enough growth height and vigour to suppress weed growth and its mounding and timid twining habit make it easily contained by a light trim of the sides and top in autumn.
Either way, as a climber or as a groundcover, the delightful fragrance is reason enough to include this plant in landscapes, particularly near walkways or open windows where it can be fully appreciated.
Andrew’s Plant of the Week…….2.12.21: Clematis ‘Hagley Hybrid’
This week I feature one of the hundreds of Clematis hybrids that have been bred, the lavender-pink flowering, ‘Hagley Hybrid’. This Clematis cultivar is one of the more recent additions to the Gardens, and unlike the majority of the species and hybrids which are grown on the south side of the Landscape Shed (apart from C. montana in the Rose Garden and C. microphylla in the Native Garden), this hybrid has been planted on the new blue arbor in the Rose Garden. The old advice of growing Clematis with the foliage in sunlight and the root system in shade would seem prudent advice for these large-flowered hybrids, if they are to be successfully grown in regions of extreme summer temperatures. C. ‘Hagley Hybrid’ was bred by Percy Picton, the Head Gardener of Hagley Hall, in 1945, and has gained a reputation as a reliable, compact vine, that has masses of flowers in early summer, and will flower again in autumn if you are game enough to prune it back in January (exposing the new tender growth to summer heat), after the first flush of summer flowers.
Hagley Hall and its Park, where Hagley Hybrid was bred, is an inspired and renowned mansion and English landscape garden in Worcestershire, a county in the Midlands of England. It was originally created in 1747 by George Lyttelton, as a memorial to soothe the grief of the premature death of his beloved wife Lucy. The landscape he created was more than a century ahead of its time. Rather than the usual, accepted, 18th century style of straight-lined formality, he created a landscape that worked with the geography and microclimate spaces in an area that was previously a deer park. It is is truly amazing to read of the poets and artists whose work was influenced by Lyttelton’s landscape, including poems by romantic writers such as Wordsworth, and exceptional works of art by Turner, Constable and Gainsborough, all attributed to visiting Hagley Park. Visits to the Park were also the beginning of tourism in eighteen century England. The Park’s pathways lead you through a sequence of spaces intended to inspire imagination, arouse emotions and stimulate the senses. And that was just the plants and landscape; there were also the architectural features and “follies” such as ruins, seats, obelisks, temples and urns, all designed to stimulate conversation, affect the mood and inspire creativity. It’s amazing what one person’s energy and vision can create; it certainly has been a lasting tribute to Lucy.
This Clematis cultivar, like the other large-flowered hybrids in the xJackmanii group, flowers on new season’s spring growth, so are easily pruned each winter by cutting down the stems to about 30 cm or lower, above ground level. I wish all pruning of shrubs was so well defined and documented as has been done for Clematis. There are three defined groups of pruning techniques that take into consideration the type of stem growth on which the flowers develop. The spring and summer flowering clematis, that flower on new spring growth, are in pruning group three, and are less fiddley than those in Group 1, that flower on last year’s growth and must therefore be pruned lightly, immediately after flowering in early Spring. The flowers of this cultivar have a range of colouration, depending on their stage of development, with the newly opened flowers much darker than the fully opened older flowers.
The dark burgundy anthers in the centres of the flowers also create a great show. Although we don’t all have the growing conditions suitable for this beautiful large flowered Clematis hybrid, it certainly evokes a mood and brings enjoyment to fill our senses, a good connection and tribute to Hagley Park where it was first bred.
Andrew’s Plant of the Week…….26.11.21: Elaeocarpus reticulatus
This week I’m featuring an Australian tree that I’m sure you are all familiar with, Elaeocarpus reticulatus, the Blueberry Ash or Blue Olive Berry (among a long list of common names). However, you may not be as familiar with the dark-pink flowering form that we have at Burnley; the lighter pink or white flowering forms are more commonly seen.
This tree is part of the Kath Deery Native Garden planting, and as with many of the plants she personally propagated and selected for her 1986 design, rather than opting for what was available in nurseries at the time, Kath found and selected this Eleaocarpus form for its outstanding qualities. Like the Grevillea victoriae subsp. nivalis I featured in July, Kath didn’t know a name for the form she used, as in 1986, no name had been allocated to this dark pink form. From what I can make out currently, the form Kath selected is likely to be ‘Dark Pink Elly’, which was granted Plant Breeders Rights (PBR) certification in 2017. The other pink form ‘Prima Donna’ is very similar (although it seems to be a lighter shade of pink), but isn’t registered as a cultivar with ACRA (Australian Cultivar Registration Authority) and hasn’t been given PBR rights.
The specimen we have at Burnley has flowered more profusely under irrigation, which is not surprising, as Elaeocarpus reticulatus’ natural habitat is in moist gullies, in or near rainforest, and in the understory of larger trees, from Tasmania to Queensland. This explains its adaptability to a range of climatic and environmental conditions, and it has become widely used in a variety of situations, including as a street tree. Some of the situations and positions where it has been planted would seem to me to be pushing the boundaries of its tolerances, as westerly aspects, temperatures above 38 degrees and low moisture soils result in leaf scorching and poor flowering
The blue fruits, which give the tree its common name, persist throughout the year in conjunction with the flowers, and are one of the reasons for its popularity as an ornamental tree. In wetter environments, Blueberry Ash may be considered a weed, as the berries (technically they are drupes), eaten by birds and thus widely distributed, germinate freely. The distinctive leathery leaves often have a silvery white edge or venation on the older foliage, and new growth is bronze and pale green, adding to the ornamental display.
However it’s the flowers that are the most attractive feature of this tree, hanging down like miniature bells, with a beautiful, fringed edge to the petals.
Andrew’s Plant of the Week…….18.11.21: Ptilotus macrocephalus
This week I bring you a triple treat, with three different species from the spectacular Ptilotus genus. All three species are currently growing in the Grasslands section of the Native Garden and the one I find most impressive is Ptilotus macrocephalus, with the common name of Feather-heads. Unlike the other two species, Ptilotus exaltatus, the Pink Mulla-mulla and Ptilotus spathulatus, Pussy Tails; Ptilotus macrocephalus is taller and therefore much easier to see amongst the surrounding grass. When I saw specimens of this species out on the Western Plains Grasslands, they were easily spotted above the vegetation and the green flower stems disappeared in the background, leaving the white cone-shaped flower heads to seemingly float in mid- air. The same display is evident in our own Grassland, and while our plant hasn’t reached its full height potential of 50cm quite yet, I’m sure in future years, as the underground tubers develop further, the flower heads will grow taller and be even more imposing.
This Ptilotus, like most of the flowering herbs growing in the Grasslands have been patiently grown by John Delpratt, and what we see flowering today, is in fact the result of several years of nurturing in the nursery prior to being planted out. Even before their nursery nurturing, John was responsible for getting permits to collect the seed from the wild, and collecting a myriad of different flowering herb species that are increasingly under threat from land clearance.
The second Ptilotus in the Grassland, P. exaltatus, is an amazing survivor, as it re-emerged from its deep underground tuber after 60mm of soil had been scalped from its bed ten years ago, when we renovated the entire bed by removing the weed-seed infested top layer of soil and replacing it with Donnybrook toppings. The flowers of the Pink Mulla-mulla are delightful and what they lack in height, they make up for in colour and the number of flower heads.
The third species, Ptilotus spathulatus, is lower growing and more ground hugging, so less prominent and you need to get down close to the ground to fully appreciate their soft and graceful habit.
Andrew’s Plant of the Week…….11.11.21: Digitalis canariensis
This week I’m highlighting a plant from the Canary Islands, the Canary Island Foxglove Digitalis canariensis, which was previously known by the generis name, Isoplexis. The Canary Islands (situated off the west coast of Morocco) are home to a wonderful collection of plants, many of which are ideally suited to low soil moisture conditions, as the majority of the seven islands have a climate that is classified as semi-arid to desert. However, the aridity factor changes dramatically from one side of the islands to the other, bcause of prevailing moist winds off the ocean, and in the middle of the three larger islands, the high altitude captures the sea moisture to create a warm, humid, subtropical climate that sustains cloud forests. It is in these moister, wooded areas that Digitalis canariensis grows, and although this sounds as if this plant requires high soil moisture, it is remarkably adaptive to a lower moisture environment.
Phil Tulk (Burnley’s previous Gardens Manager) originally planted this Canary Island Foxglove in the Perennial Border in the mid- 1990s, from where it was transplanted into the Pine Bed a decade later, when I tried (unsuccessfully as it turned out) to eradicate the Potato Weed (Solanum cardiophyllum) from the Border, by removing all the desirable plants and spraying the Potato weed with herbicide for two consecutive summers. The Foxglove has performed very well on the western side of the Pine Bed, under the large Pinus canariensis (Canary Island Pine), in a bed and aspect we consider to be horticulturally challenging. This plant has been a reliable, long lived, evergreen perennial shrub, that needs little attention or effort for a great reward. The flowers begin in late October and continue all the way through to autumn. Can’t ask much more of a plant than that.
The flowers are an usual gold, soft apricot, orange colour and are rich in nectar, borne in upright spires (racemes). The glossy, dark green foliage is spaced slightly apart along the branches, so is well displayed, and the younger stems have a prominent dark red colour, which also adds to the ornamental display.
Pruning of the Canary Island Foxglove is straight forward, always leaving the new, yet-to-flower stems and pruning the spent flowered stems in winter, lower down the stems to encourage new growth to develop.
Andrew’s Plant of the Week…….04.11.21: Iris tectorum
This week I’m highlighting one of the many Iris that are currently flowering. While the Bearded Iris (Iris germanica) is what we tend to focus on; the Rose Garden for example has numerous cultivars that are flowering now, the Japanese Roof Iris, Iris tectorum is one species probably less well known. This species, although native to China, Korea, and Myanmar, has become naturalized all over the world, including India, Bhutan and North East America. There are several theories on why this Iris was grown in the clay of the roof thatch of Japanese houses (which is how it gets its common name). One theory is that during the Great Japanese famine of 1640-1643, when up to 100,000 people died of starvation, the Empress decreed that all cultivated land was only to be used for growing food. However, since the rhizomes of the iris were ground up and used to make hair dye and a white, cosmetic face powder, the innovative Japanese women started growing the iris on their roofs, thereby bypassing the decree forbidding flowers being grown on the land surrounding their houses.
Their shape, and the overlapping, weeping habit of the leaves of this iris have an ideal habit for growing on roofs, as the pale green, sword shaped leaves, which have a fan-shaped habit, provide an excellent and ornamental flat covering for the roof. The leaves, like the similar Iris japonica, always fall in one direction; their natural habit is to fall sideways rather than be erect like the Bearded Iris. This weeping foliage habit, in combination with the creeping short rhizome, provides good coverage, whether on the ground or on a roof.
The Iris genus is diverse and interesting, with different species covering a wide range of tolerances. Some species will grow in water, others on damp margins; some are herbaceous, dying down each winter, and others are evergreen and have high aridity tolerance. While the species I’m highlighting this week doesn’t flower for an extended period, a few weeks at most, the delightful purple flowers and beautiful green foliage make it an ornamental plant to consider for dappled shade, or for sites in full sun. .
Like all rhizomatous iris, this species will have improved flowering with periodic division, as it is only the end point of the rhizome that produces the flower and foliage, and if the old unproductive part of the rhizomes isn’t removed, plant clumps become crowded, and flowering will diminish.
PS dont forget to click on the imagesfor a bigger view
Andrew’s Plant of the Week…….27.10.21: Cotinus coggygria ‘Royal Purple’
This week I’m featuring a plant that most of you will be very familiar with, the Smoke Bush, Cotinus coggygria. The cultivar we have, ‘Royal Purple’ is one of the older varieties and is slightly different to other well- known purple leaved cultivars, such as the popular ‘Grace’, as it is slower growing, and therefore less vigorous, and about half the height.
Although there are two non-purple leaved cultivars, ‘Flame’ and ‘Golden Spirit’, the purple leafed forms tend to be what we associate with this species. The ‘Royal Purple’ cultivar doesn’t have the incredible autumn colour range of ‘Grace’, being more uniform scarlet in colour, but if intense, dark purple foliage is your prime consideration, then ‘Royal Purple’ is hard to beat.
As far as a deciduous shrub goes, Cotinus coggygria ‘Royal Purple’ ticks all the desirable boxes, as it is adaptable to a wide range of soils, will grow in either full sun or shade and has low soil moisture requirements. Many of the cultivars of this shrub are often cut back hard each year, either coppiced or pollarded, however they can also be left unpruned. Heavy pruning does impede flowering, the cloud like, fluffy flowers are what gives the plant its common name “Smoke Bush” and is one of the distinctive, delightful attractions of this species and its cultivars.
Andrew’s Plant of the Week…….13.10.21: Centranthus ruber
This week my plant choice may raise some eyebrows, as some of you may wonder why I have chosen to feature a plant regarded as an environmental weed. Centranthus ruber, which has a variety of common names, the most common being Red Valarian or Kiss-me-Quick, is, I’m sure, well known to all of you. This plant was one I remember from my childhood and hard to forget. It has become naturalised all over the world and I often see it in the TV series Doc Martin, poking out of a stone wall. However it’s not just cute seaside English villages where you come across this easily identifiable plant, you also could find it growing in the cracks of walls and concrete paving, inhospitable spots, where you marvel at its tenacity.
Here at Burnley, we have a patch of it down near the library, where it fights it out with the Juniperus sabina (no contest there) and Osteospermum (African Daisy), where in recent years, the Centranthus seems to be gaining some real estate advantage. These three plant species have been growing together for about 30 years, in a bed that has soil heavily impacted by the root system of the large, Heritage-listed Elm.
The bed is unirrigated, apart from a small area where in 2019, we planted several Cercis siliquastrum (Judas Tree). So, the point is, plant life on the western side of the Library is difficult. The collection of banksias and Leptospermum we planted down there in the early 1980s, (when the Library was built, didn’t survive; little by little, they faded away and then died, allowing the other three to get on with what they do best, survive and prosper. Down in this bed, water is scarce, root competition is fierce and western sun exposure is extreme. As the bed is bordered by roads on two sides and paved pathways on the others, the ability for the seed of the Centranthus to germinate and colonise nearby has been near impossible, so here at Burnley, it hasn’t become a spreading weed.
There are at least five distinct colours of Centranthus, a dark red, the lighter red we have, the more common pink, a darker pink and a taller growing, white flowering form. The appeal of Centranthus is not only their high tolerance to arid conditions but also their ability to flower for long periods, with a big flush starting in September, that continues through to autumn, albeit not as abundant as the late spring display. The ability for Centranthus to tolerate limestone soils, grow in brick walls (lime mortar) and survive in concrete cracks is well known, and it provides beauty where normally little else would grow. Introduced to Melbourne as early as 1855, if not earlier, it was only considered a naturalised weed from the early 1980s.
The blue green foliage of Centranthus ruber has some ornamental appeal, and their maintenance is very easy: we treat them like long-lived perennials, with the foliage cut to the ground in winter each year; it then re-shoot from the base. Older plants become woody and can die out, but seed germination fills out any gaps and makes a self- sustaining clump.
Andrew’s Plant of the Week…….13.10.21: Prunus Sato-zakura Group
This week, despite the fact that I once again feature a Japanese plant (three in a row), I can’t resist featuring the beauty of the pink flowering Japanese Cherry at the bottom of the Oak lawn. This is one of those spring flowering plants that will only look its best for perhaps a fortnight, but the short flowering period makes you appreciate it even more, knowing it will soon be all over until next year.
The Japanese have been breeding and admiring cultivars of the flowering cherry for more than a thousand years, from as early as 794 AD, and consider the flowering season a spring ritual of renewal. While at first this ritual was only celebrated by the imperial family, it was eventually celebrated by all Japanese. The brief flowering season is not only an international tourist attraction, but also a celebration for Japanese families, who sit under the trees with picnics, write poetry, sing, and toast each other for an auspicious year to come.
The nomenclature of Japanese Cherries has been difficult to sort out, with the parents as well as the cultivars unable to be definitively assigned, as there are so many previous synonyms and hybridisation that has taken place, over a long period. In 1984 a very practical solution was endorsed, it was decided to group all of them together under one name, the Prunus Sato-zakura group. Sato-zakura means “village-cherries”, a good representation of how they developed and were used, with cherry trees more often planted in public spaces in Japan, rather than in people’s private gardens.
Burnley has three different cultivars of Japanese Flowering Cherry, with this double form flowering slightly later than the other two single-flowered forms, on the east and south side of the Sunken Garden. Although flowering cherries are not considered long lived (for a tree), you can still expect to get 40-50 years from them, with very little pruning being necessary.after the initial formative pruning.
Andrew’s Plant of the Week…….08.10.21: Wisteria floribunda ‘Honbeni’
This week I feature another Japanese plant, one of the many cultivars of the well-known and admired Wisteria floribunda; the lavender pink-flowered cultivar ‘Honbeni’. This pink form is sold in nurseries under numerous other cultivar names, such as ‘Rosea’, but I have followed the name Peter Valder uses in his monograph on the genus Wisteria.
Following on from last week’s story of Stachyurus praecox, Wisteria floribunda and the similar Wisteria brachybotrys were likely to have been part of the collection of plants introduced into cultivation in Europe in the late 1860s by Seibold. Others before him, also physicians employed by the Dutch East India company, surreptitiously collected and documented plant specimens. By 1633, the only Europeans allowed access to Japan were the Dutch, as the Spanish and Portuguese were thrown out because of their over-zealous religious conversion activities.
However even for the Dutch, access was highly restricted, with the Dutch East India Company confined, from 1638 to 1858, to an artificial island 120m long and 75m wide, named Dejima, in Nagasaki Harbour. Their only opportunity to visit the mainland and collect plant specimens was when they were compelled to do the annual court journey of homage to the shogun, in the city of Edo. To ensure they could continue their stay in Japan, the Dutch were forced to be humbled by crawling on their hands and knees and bowing their heads to the floor before the shogun.
This annual trip coincided with the flowering season of Wisteria floribunda, where observations were made of the incredible size of individual plants and the wondrous display of the pendant flowers. One of several Wisteria specimens growing in Japan, and deemed a National Treasure, is thought to be over 500 years old, and in 1861 was recorded as having a trunk diameter of 2.1 metres and a spread of 18m x 31m. It was situated at a tea house, and was a great boon to business, as customers would travel great distances to sit under the 1200mm-long hanging racemes of flowers. There is a famous Japanese tourist attraction, a Wisteria Garden named Ashikaga Flower Park. It is 8 hectares in size, the same size as the Burnley Gardens, and contains 80 metre long Wisteria floribunda pergolas and 8 metre high walls covered in Wisterias, that resemble waterfalls. One of the wisterias in the Flower Park was planted in 1861, the same year in which the Burnley Gardens began to be planted up.
As for our own humble 20 metre long Wisteria Walkway at Burnley, planted up in 2018, it is just starting to perform as anticipated, with the long flowers hanging down beneath the archway. The cultivar ‘Honbeni’ was a surprise, as I had ordered ten ‘Royal Purple’ and it was only when they began to flower two years later that I discovered that six out of the ten were the pink, rather than the purple cultivar I had ordered. I’m not disappointed, as the pink is rather lovely and tends to flower slightly later than the purple, thereby extending the flowering season to more than a month.
Andrew’s Plant of the Week…….30.09.21: Stachyurus praecox
This week I’m featuring a deciduous shrub that I suspect most of you may have seen growing in Botanic Garden situations, rather than something you have observed in suburban gardens. Stachyurus praecox, sometimes referred to as Spiketail or Early Stachyurus, is native to the warmer, temperate areas of Japan, where it grows on the margins of forests, often as a pioneer plant species that establishes after disturbance or clearing. The specific epithet (the second part of the Latin name), praecox, means early, as this is the earliest of the eight Stachyurus species to flower.
If there was one plant you could choose to epitomise the renowned qualities of Japanese culture; for instance, the grace, understated beauty, and minimalist perfection of Japanese art, cuisine, and gardens, then you couldn’t go past Stachyurus praecox as a fine representation of these qualities. For a start, there is the arching, reddish-brown shiny branches, that being deciduous are quite prominent in winter, but also easily seen even when the shrub comes back into leaf, as there is a sparse, bare minimum of foliage along the branches that allows the ornamental stems to be easily seen, even in full leaf.
However, it’s the flowering period that really makes this shrub so memorable and provides such beauty, grace, and prominence. The pale, lime-green cup-shaped flowers are borne in pendulous racemes which look like strings of pearls, hanging vertically in a curtain. The racemes of flowers can be 10-15cm long, and extend 30cm along the ends of the branches. The flowers start to emerge just before the foliage and the racemes continue to lengthen as the leaves unfurl.
Interestingly, this shrub is considered dioecious, with male and female flowers on separate plants, even though natural populations in Japan have some bisexual plants that only seem to produce male pollen, with the separate female plants producing the fruit. In Japan, the flowers are pollinated by solitary bees and hoverflies, and from the 1830s when this plant was introduced, the early flowering (late winter) attribute was one of the attractions for European and American gardeners.
Also of note is the German explorer and physician, Philippe von Siebold, who, with the help of local Japanese, (and closely followed by the rest of the world) collected Stachyurus praecox, as well as thousands of other Japanese plants, artifacts and animal specimens, and introduced them to Europe. Von Siebold’s cultural collecting exploits were especially significant, as Japan was socially and politically isolated from the rest of the world at this time, with strict trade controls in place until 1868. He managed to illegally smuggle tea seed out to Java, a Dutch colony (the first time tea was grown outside of Japan), but he was caught and subsequently expelled from Japan in 1829 for illegally possessing a map of northern Japan (they thought he was a Russian spy). In his eight year stint in Japan, he managed to collect 2,000 living plant specimens, all of which he brought with him when he was expelled.
Stachyurus praecox flowers on last season’s growth (old wood), so should be pruned after flowering has finished. The arching branches can be cut to the base, but in fact little if any pruning is needed. The flower buds develop in autumn and overwinter on the branches, and can therefore can be damaged by frosts and cold dry winter winds. It has good autumn colour, the foliage turning tones of red and orange.
Andrew’s Plant of the Week…….22.09.21: Hyacinthoides hispanica
This week, despite that fact we know Blue Bells so well, and may take their attributes for granted, I couldn’t ignore the huge swathe of Spanish Blue Bells that are covering the entire South-eastern bed of the Rose Garden as the choice for this week’s Plant. Although we have numerous patches of Hyacinthoides hispanica throughout the Gardens, with the patch under the pink flowering Cherry (Prunus subhirtella ‘Pendula Rosea’) in the Kirkhope Rockery looking fantastic, and another patch along the Orchard borders also eye-catching, the Rose Garden bed display dwarfs all the others by a huge margin.
Its hard to know how many years it has taken to achieve the large bulb density in the Rose Garden bed, there are thousands of bulbs there now, and while visitors, students and staff have all seen and known about this haze of blue down at the furthest south-eastern end of the Gardens for years, somehow the numbers seem to have crept up in recent times to now extend further into the bed.
Prior to the early 1980s when this corner of the Garden was planted up with roses, the area featured a secluded lawn, known to students and staff at the time as the Lovers Lawn and although the lawn made way for the roses, the bed to the east of it has been reasonably intact since the Burnley Gardens were first planted up in the 1860s and 1870s. One tree in particular in this South-eastern bed, the large Magnolia grandiflora, was a well-loved climbing tree for the resident children of the Principal of the College in the 1950s and 1960s and the children of the Curator of the Egg Laying Competition who also lived in the Gardens during this time (the Kneen and Macauley families), with one of the Kneen children using a lower branch of the Magnolia as a pretend horse to ride
I’m digressing somewhat from plants but if you’re wondering about what or why Burnley had an egg laying competition and a curator to supervise it, it’s a fascinating story worth briefly repeating. From 1911 until 1974, Burnley was involved in improving the standard of the poultry industry, which had direct input into improving the quality of birds that most households had in their backyards during this period. The idea was for poultry farmers to ‘submit’ their champion birds to be assessed for their egg laying capabilities, with the winner at the end of the year getting bragging rights to sell their chicks to all and sundry. Egg-laying was monitored to make comparisons between breeds and individual birds, and a daily record kept of their egg laying. There was no chance of interference or slipping an extra egg into the cage, let alone telling porkies on how many eggs birds had laid, as the chickens were supervised and looked after by the Poultry manager. This role was done by the same family for fifty-eight years, firstly by the father, then by his son, a remarkable achievement. The chicken sheds, where the nursery is now, were cleaned out each January by the new first year students, something they will never forget and the best they could say about it was, it was a bonding experience.
Editors note: I was a first year Associate Diploma student in 1985, and we were still shoveling out those sheds then. A terrible job. the smell! The dust!
Andrew’s Plant of the Week…….16.09.21: Micromyrtus ciliata
This week’s plant almost made it as a Plant of the Week last year, but the fierce Spring competition relegated it to the backburner. Micromyrtus ciliata, the Heath-myrtle, doesn’t deserve such neglect, as it is an outstanding, well-known shrub that is highly regarded and praised by native plant groups. If you have ever visited the Grampians-Gariwerd, I’m sure you would have come across this species and it is also found just over the border in South Australia, as well as in New South Wales, in a variety of habitats.
In Victoria, there are two distinct forms of Micromyrtus ciliata: the taller, white flowering, more upright form, which grows in the sandy soils of north west Victoria, and the dark-pink tinged flowering form, a low, sprawling groundcover, that grows on rocky soils such as those of the Grampians. This ground covering form tends to be the preferred option when selecting the species, and generally gets rave reviews for its drought tolerance, long flowering season, and minimal maintenance requirements. What more could one ask for?
The Heath-myrtle in the Ellis Stones Rock Outcrop Garden is well matched with the pink tinged granite rock slabs that Ellis carefully positioned in 1962. I mentioned a little about Ellis Stones last February in a previous Plant of the Week, but didn’t mention the fact that there was a 1962 native plant planting list, selected from the Bodies’ Nursery catalogue, that was the basis of the planting design.
Interestingly, Beverly Hanson, a Burnley graduate at this time, was employed to select and source the native plant material for this and later examples of Stones’ designs. In 1962, there was very little choice for sourcing native plants, with Bodies’ Nursery being one of the few to supply the limited interest in using native plants at that time.
It was great to obtain this original planting list, complied from the Bodies’ catalogue, as well as the actual design that Ellis had done in 1962, when Sandi Pullman discovered them in the state library in 1999, while researching for the re-planting of the bed. I was amazed to see so many familiar plant names on this list that Beverly did, one of them being Micromyrtus ciliata.
Although like several others on the 1962 list, the name, for some unknown reason, had a line drawn through it, Micromyrtus ciliata was nevertheless selected as one of the plants used to re-plant the bed, and it certainly has lived up to its reputation as being a high value, low maintenance groundcover that also complements the naturalistic rock work that Ellis Stones was famous for. True to his belief that the rocks should be the hero in his designs and the plants should provide a secondary, complementary role, the Heath-myrtle ties in nicely with the rocks and doesn’t dominate the granite rock outcrops and dry, pebble stream bed that Ellis included in his original design.
Click on the link to see the plant list from 1962. It’s most interesting. Msany names will be familiar to those who were part of the 1960-70s native garden movement. 1962 plant list
Andrew’s Plant of the Week…….07.09.21: Kerria japonica ‘Pleniflora ‘
This week, at the start of Spring, there is so much to choose from for the Plant of the Week. The next 6 to 8 weeks will see the Gardens looking at their best, with some of the plants in the Gardens only flowering during this short, Spring season.
The plant chosen for this week, Kerria japonica ‘Pleniflora’, is one I learnt in my first year of studying horticulture, and it has remained a favourite ever since. This double-flowered form of Kerria japonica seems to have a few common names, most of them evocative of the flower shape, with names such as Bachelor’s Buttons and Japanese Rose reflecting the shape and form of the flower. Being deciduous, in winter Kerria japonica tends to almost disappear into the background, with the green upright stems blending into the surrounding vegetation. However, in early Spring the golden yellow pom-poms suddenly burst out of the arching stems, and are closely followed by the deeply veined, serrate-edged leaves, which have that vibrant green colour we often associate with new Spring growth.
The non-aggressive suckering habit ensures that, once flowering has finished, last years canes can either be cut back or fully removed, to provide the new flowering wood for the next Spring’s display. Although referred to in our Burnley Plant Guide as having an average to poor drought tolerance, we grow this kerria in some dry conditions under trees, and although they don’t perform to their optimum, they are versatile enough to flower and survive reasonably well, albeit needing the supplementary irrigation that the majority of beds in the Gardens have.
One of the reasons I like this plant is the colour and movement it provides in the mid-background section of garden beds, as the green arching stems and small leaves seem to disappear in the background and the prominent golden yellow balls seem to dance and sway in the wind, as if suspended unattached in mid-air. Planted as a specimen shrub in a more open situation, this 2.5 metre rounded shrub provides a fantastic feature display and it is this versatility that makes this shrub so adaptable. Kerria japonica is recommended for planting in eastern, southern or semi-shaded situations, protected from bright, mid-day or afternoon sun, to avoid the flowers deteriorating, fading and losing their golden yellow hue.
Andrew’s Plant of the Week…….02.09.21: Acacia acinacea
This week on the first day of Spring, and as it’s also National Wattle Day, I couldn’t pass up the opportunity to feature the well-loved Gold-dust Wattle, Acacia acinaceae. With a native habitat range in three states, South Australia, Victoria and New South Wales, as well as the National Capital Territory, this acacia is a bit like choosing a lucky dip, as depending on the
particular plant you have, it’s uncertain what height and form you will end up with. Of course, you can propagate this acacia from endemic (single defined geographic area) seed sources, which will give more certainty on its height and form, but if you are purchasing a plant from a nursery, you could end up with either a tall 2.5-metre shrub, or a low mounding
shrub half that height. Either way, what they all have in common is the delightful bright yellow flower heads that seem to contrast so beautifully with the clear blue sky of Spring.
We have several specimens of the Gold-dust Wattle in the Gardens, with two clumps in particular being quite different, one has a more upright habit, with long arching sprays of flowers, and small leaves (in the case of most acacias, the “leaves” are actually modified petioles known as phyllodes) and the second clump is far lower and more compact, with larger phyllodes, shorter flowering stems and fewer flowers. Many forms seem to sucker well and certainly all can be severely cut back to any growth point on the stems to rejuvenate the shrub.
The flowers are nicely fragrant, especially on a warm sunny Spring day, and although some plant reference material on this species says otherwise, Acacia acinacea is relatively long lived, and is tolerant of almost all soil conditions, apart from perhaps waterlogged and highly compacted soils.
The Gold-dust Wattle performs better in full sun to partly shaded conditions, as plants grown in full shade perform poorly. Like so many of the acacias we have the option of growing, this species is highly drought tolerant, as illustrated by the tube stock we planted on the embankment of the Boulevard (first planted up by Minette Russell-Young in the 1970s), which have survived with just an initial watering after being planted.
Andrew’s Plant of the Week…….25.08.21: Phebalium squamulosum ‘Starry Cluster’
This week we once again highlight a plant from the Rutaceae family, Phebalium squamulosum. Of the 33 species in the genus Phebalium, only one of them isn’t endemic to Australia, but to North Island, New Zealand. There are numerous cultivars, forms and ten subspecies of Phebalium squamulosum, and the cultivar I’m featuring this week is ‘Starry Cluster’. This cultivar is perhaps slightly taller than some of the others available but just like numerous other plant cultivars, sometimes it’s difficult to distinguish between the subtle differences of cultivars or subspecies. All phebaliums will provide a wonderful flowering display that smothers the entire shrub, over an extended period from late winter to spring.
The subspecies of Phebalium squamulosum have a large habitat range, all of them found on the east coast of Australia, with one subspecies in far north Queensland and the remainder growing from southern Queensland right down to Victoria. It’s therefore no surprise that there are so many subspecies, as the climatic conditions of Queensland, N.S.W. and Victoria are so varied. While some of the subspecies have white flowers, the colour I most associate with subspecies squamulosum is a pale to golden yellow, the exact shade of yellow often changing depending on its stage of flowering, and whether or not the sun is shining. The five petals and extended stamens seem to capture and intensify the reflected sunlight, giving the appearance of a low shrub radiating golden light.
We often think that Phebalium species, while they are drought tolerant, are more suited to partly shaded situations, but they are well able to cope with even a hot westerly aspect. The flower buds are also very ornamental, as are the leaves and stems, as they all have a slightly speckled colour variation that gives the shrub good ornamental qualities all year round. A light clip once the shrub has finished flowering in late spring or early summer, is all this genus needs, rather like the Philotheca I featured last week.
Andrew’s Plant of the Week…….20.08.21: Philotheca myoporoides subsp. acuta
This week I bring you a genus you are probably very familiar with, although some of you will have known it by its previous name, Eriostemon. Thirty nine Eriostemon species were transferred into the genus Philotheca in 1998, the latest stage in a long story that even included Australian botanist and plant collector William Blakely, who worked for the NSW National Herbarium and, with Joseph Maiden, collected, described, and classified many members of the genus Eucalyptus. In fact, Maiden named a eucalypt after him, E. blakelyi, to honour his contribution to the classification of the genus. Blakely’s method of using buds and fruits, as in his “A Key to the Eucalypts”, is still used today to distinguish between species.
Meanwhile, back to the plant I’m featuring this week, Philotheca myoporiodes subsp. acuta, with the common name of Wax Flower (we are probably more familiar with the species name rather than the subspecies, as P. myoporiodes has been a well-known and frequently used shrub for many decades). A delightful difference in this subspecies is the darker pink flush to the emerging buds, a wonderful addition to the long-flowering mass of blooms that cover the entire canopy of this lovely, rounded shrub. This subspecies is very drought tolerant, and has a wide habitat range, from south of Cobar in Central Western N.S.W, to further east nearer the coast, where it’s found growing on sandstone hilly areas above water courses. Being a member of the Rutaceae, Philotheca, like other well- known genera in its family, such as Correa and Boronia, has a dense, white, fragrant, fibrous root system that seem to give some competitive advantage in soil exploitation, a great attribute for survival in the harsh, drought ravaged, rocky environments where they grow. Philotheca has the desirable trait, which I’ve mentioned in previous POTW’s, the ability to respond well to hard pruning, prolonging the advantageous juvenile qualities of plant growth . The ability to re-use the stored underground root potential to re-activate dormant buds on the lower sections of branches is a great way to rapidly regrow shrubs that have either become too large or are under-performing in terms of their flower potential or aesthetic attributes.
Burnley has two areas where we grow Philotheca myoporoides, with two shrubs in the Kath Deery Native Garden that originate from the 1987 planting, so have proved long lived and reliable. I’ve only needed to hard prune these shrubs once since they were planted; in every other year a light clip in late Spring has been sufficient to keep their rounded, tidy habit. The other more recently planted Philotheca subspecies in the Ellis Stones Rock Outcrop Garden are growing rapidly and are flowering exceptionally well, so provide a delightful, eye catching display at the front of the bed.
Editors note: the story of the naming of this shrub is rather long, but you might like to look through it, if you are very patient.
It starts with JE Smith naming the genus Eriostemon in 1798, in London
Smith, J.E (1798), The Characters of Twenty New Genera of Plants. Transactions of the Linnean Society of London 4: 221 [tax. nov.]
Then de Candolle named E. myoporoides in France, in 1824
Eriostemon myoporoides DC.
Candolle, A.P. de in Candolle, A.P. de (ed.) (1824), Rutaceae. Prodromus Systematis Naturalis Regni Vegetabilis 1: 720 [tax. nov.]
Meanwhile Philotheca was named by Rudge in 1816
Rudge, E. (1816), A Description of several new Species of Plants from New Holland. Transactions of the Linnean Society of London 11(2): 298, t. 21 [tax. nov.]
Eriostemon myoporoides var acuta was named by Blakely in 1941
Then in 1998 Paul Wilson from WA undertook a major revision that left only two species of Eriostemon (E. australasius and E. banksii) in that genus, and transferred all the other species into Rudge’s genus Philotheca.
Wilson, Paul G. (16 September 1998), A taxonomic review of the genera Eriostemon and Philotheca (Rutaceae: Boronieae). Nuytsia 12(2): 249
And in the same year Bayly revised the species Eriostemon myoporoides, transferring it to Philotheca, and creating numerous subspecies, including subsp acuta which was formerly Blakely’s var. acuta.
Bayly, M.J. (1998), Notes on the Eriostemon myoporoides (Rutaceae) species complex, including new names and a new generic placement in Philotheca. Muelleria 11: 121 APC [tax. nov.]
I wonder if that will be the end of it?
Andrew’s Plant of the Week…….12.08.21: Prunus ‘Pollardii’
This week I’m featuring a beautiful, resilient blossom tree, Prunus ‘Pollardii’, the Flowering Almond, also known as the Pollard Almond. The tree in the Herb Garden is very old and was part of the backyard of the Principal’s residence garden before the cottage was removed in 1980. Very little remains of the private back garden, with a small section of crazy paving, Coldstream rock walls, a stone columned Garden seat, a clump of black bamboo and a Jacaranda being the only other likely indication of what had existed from the century-long era when the Principal lived in the Gardens. This Prunus ‘Pollardii’ gave me quite a fright in early 2019 when the entire tree suddenly died in a matter of weeks. Fortunately, the resilient root system sent up numerous suckers in the spring of 2019 and the tree is once again providing joy and appreciation to those fortunate enough to walk through the Gardens.
This prunus is a hybrid between an almond (Prunus dulcis) and a peach (Prunus persica), which turned up as a chance seedling in 1864 on Joseph Pollard’s property near Creswick, on what is now the Buninyong Bowling Club. This hybrid has great characteristics of both parents: it has the early flowering, excellent drought-tolerance and longevity of the white flowered almond with its dark pink stamens, and the beautiful large pink flowers of the peach. The combination of almond and peach gives an even larger flower than either parent, and has the advantage of not suffering from Peach Leaf Curl (nor does the almond).
It is interesting to note that Prunus ‘Pollardii’ is also one of the parents of a New Zealand-raised hybrid, Prunus ‘Wrightii’, which looks very similar, apart from having smaller flowers.
August is a big month for the flowering of almonds, and by now, or very soon, 277,000 beehives will have been distributed throughout the almond growing regions of Southern Australia. On one almond farm alone, near Robinvale in northern Victoria, 1,800 hives have been transported to help with the tree pollination to ensure a successful nut harvest this summer. This vital part of the almond industry is a tricky exercise in logistics for the apiarists, who need to transport their hives over long distances, over several days, to get to the almond farms. Something to think about next time you sip on your almond milk latte.
Editors note: peaches and almonds are almost identical genetically: an almond is a dryland equivalent of a peach. and they hybridise readily. The two are deliberately crossed in the northern hemisphere to produce drought tolerant rootstocks, and cold tolerant almonds. The hybrids can be propagated by budding and grafting, or cuttings, which are the usual methods for fruit trees, but can also be grown from seed and grown on their own roots, like our tree.
Andrew’s Plant of the week…….05.08.21: Puya ferruginea
This week I bring you something a bit different, a plant that has been introduced to the Gardens through the research into suitable plant species for Green Roofs. Puya ferruginea is certainly well suited to the often shallow, low organic substrates used on green roofs – the native habitats of this plant give a very promising indication that it can withstand the large environmental extremes that green roofs are exposed to. Puya ferruginea has the generic common name Achupalla, which is used for multiple Puya species found in South America. This Puya species grows from Ecuador down to Peru and Bolivia, in a huge altitudinal range, from 4000 metres down to 400 metres, where it is found growing in a wide range of habitats, from rocky cliffs to grasslands. Any plant that can thrive, let alone exist, on a rocky cliff has some obvious potential for use on green roofs. On our own Demonstration Green Roof, where we first grew this species, the summer temperature on the roof can be over 50 degrees C, not a place for any faint-hearted plant.
The Burnley Plant Guide has some useful information on the genus Puya, telling us that the Bromeliad group, which includes Puya, has the same type of metabolism as cacti, known as Crassulacean Acid Metabolism (CAM), which enables plants to survive in low moisture environments by opening their stomata only after sunset, to avoid plant moisture loss during the daylight hours.
The slightly spiny, narrow silver-green foliage of this Puya certainly gives the impression of being drought resistant, and the rosettes of twisting foliage clumps bulk up quickly to produce numerous new rosettes. It is the flowers though that make the plant so striking and interesting, both when they are fully open, and also when they are finished. The greenish yellow and purple-streaked, translucent white flowers have an unusual shape and structure and it’s interesting that in South America they are pollinated by bats, whereas other Puya species are pollinated by Hummingbirds, something you can well imagine when looking at the downward sprays of flowers that Puya ferruginea tends to have. The spent flower is perhaps even more ornamental, as they have a purple red twist to the downward-pointing spike that looks like a twisted piece of wax.
The other specimen of Puya ferruginea we have at Burnley is growing in the Grey Border. This is one of the few areas in the Gardens that lacks the legendary fertile Burnley soil, a result of the site having been leveled and filled with sandy loam when its buildings were removed many decades ago. This water repellent soil, which also contains the roots of the neighboring large Moreton Bay Fig (Ficus macrophylla), is a very limiting and restrictive place in which to grow plants. The initial scheme, to create a winter display border after the buildings were removed, was soon abandoned when it became obvious that the soil would not allow this type of planting. Of the plants that did survive, it was the silver and grey foliaged plants that coped well, and thus out of necessity, the beds began to be planted up with the predominantly silver and grey leafed species we have today. So this area was named for the plants that could thrive and survive there, rather as the result of a deliberate plan to create a silver and grey foliaged border! Practicality won out over persisting with growing plants that couldn’t cope with the environment of hydrophobic soil and root competition. This was all happening in the early 1980s, at a time when, initially through the plant philosophy of then Senior Lecturer James Hitchmough, Burnley became focused on and renowned for teaching plant tolerances. In effect this meant sending graduates out into the workforce who assessed the environmental conditions of landscapes, and then chose plants suited to them, rather than trying to change the environment to suit the plants. This philosophy was the basis of the four volume Landscape Plant Manuals, which later morphed into the on-line Burnley Plant Guide we have today. This Guide is a serious achievement and a consolidation of decades of work, that has become the cornerstone of how plant materials are taught at Burnley.
Andrew’s Plant of the week…….30.07.21: Camellia japonica ‘The Czar’
This week I’m featuring Camellia japonica ‘The Czar’, that tells a story of the crushed hopes and dreams of a nurseryman, and also illustrates how mysterious plants can be. Camellias are universally well-known and have a long and successful breeding history in Australia, including at Burnley with Alex Jessup, a former Principal and Camellia breeder. Of the thousands of Camellia species, hybrids, and cultivars in the world, the most significant would be the Camellia sinensis, the leaves of which are used to make tea.
Like so many other plant species, seedlings of camellias can often produce something new and extraordinary. This was the case when Neil Breslin, an Irishman living in East Camberwell, selected the cultivar ‘The Czar’ from a batch of seedling camellias he propagated. Neil Breslin was a garden architect (a previous name for a Landscape Gardener) who worked in Victoria between 1872 and 1912. After his death in 1912, a sharp-eyed Nurseryman, R.M. Hodgins, from Hodgins Nurseries in Essendon, recognising the potential of this extraordinary new camellia flower, approached the daughter of Neil Breslin, and purchased all the stock plants for his nursery business, except for the original, larger specimen that was in the garden of the East Camberwell house.
Hodgins then spent much time and effort propagating this Camellia cultivar to build up a stock of over 800 plants to sell in his nursery. Alas, the public didn’t share his insight and passion for this large-flowered camellia, and he ended up reducing the price to sell them all off, never again propagating and selling them. The reduced selling prices of 2-5 shillings each (depending on the pot size); in today’s dollar terms, converts to $14-$28 each, showing he still wanted to get some return for his effort.
It wasn’t until 20 years later, when the plants he sold matured and developed into impressive shrubs that the public finally realised how magnificent this large- flowered camellia was. In fact, by the 1950s it was a common sight in suburban gardens and newspapers and gardening magazines were espousing the virtues of its winter flower colour. It’s interesting that the original plant in the East Camberwell garden, considered by Hodgins too large to transplant in 1912, was transplanted to the RBG (Royal Botanic Gardens in Melbourne) in 1952, no small endeavour, as it was by then (some 50 years later) “ten ft high and 13 ft across”, where, as far as I know, it is still growing.
As it was the most popular Australian camellia in the late 1940s and 1950s, it’s no surprise that Emily Gibson used two of them when she planted up the Island Beds to hide the Administration building from the Gardens, after the building was completed in 1949. The largest of the two, on the south side of the South Island bed, flowers well and needs no attention to maintain its dense, compact shape.
Now to the mysterious part of this cultivar. It concerns the tendency for an individual branch, or perhaps an entire shrub, to mutate, which is referred to as a ‘sport’. The usual light crimson-flowering ‘The Czar’produced a branch with a pure white flower. This occurred in a Rosanna* garden in 1969 and the resulting plant was given the cultivar name of ‘Fiona Capp’ (named after a grand-daughter). It seems extraordinary that such a complete flower colour change can occur some 70 years after the cultivar was first raised from a chance seedling in east Camberwell. The distinctive yellow, prominent stamens in the centre of the flower are present in all cultivars.
* a north-east Melbourne suburb
And dont forget to click on the images for a bigger view.
Andrew’s Plant of the week…….21.07.21: Grevillea preissii subsp. glabrilimba
This week I can’t resist re-visiting the Grevillea genus; this time it’s a Western Australian species, Grevillea preissii subsp. glabrilimba, the Spider Net Grevillea. This low shrub is worth growing just for its silver/grey foliage, however, when it flowers throughout winter, it really grabs your attention with its masses of bright red, well displayed flowers. This coastal species grows on limestone soils and has a limited natural habitat range that extends about 200 km north and south of Perth. It is suited to dry, low humidity summers, however it is known to perform well on the more humid eastern coast as far north as Brisbane.
In the past there had been some confusion about the correct species name of this grevillea, as it was thought to be a subspecies of Grevillea thelemanniana. It has now been recognised as one of two subspecies of Grevillea preissii, which also includes several cultivars and a few hybrids, so there is plenty of choice in what is available. However, the naming of the subspecies, cultivars and hybrids seems to be inconsistent between nursery stockists, so it’s still confusing as to what is purchased. The grey foliaged specimen we have in the Kath Deery Garden has been there for several decades and was either planted as part of the original planting in 1987, or within a few years afterwards. We also have a second, more recently planted, green foliaged specimen, likely to be a Grevillea preissii subspecies, in a nearby bed that tends to flower earlier than the grey foliaged subspecies.
The great thing about all the Grevillea preissii forms is their ability to be regenerated by hard pruning, as they have lignotubers (dormant growth buds at the base of the plant) from which new growth can emerge. This is a great advantage to ensure plant longevity, and to keep it looking compact and healthy indefinitely. We have only hard pruned our grey foliaged specimen once since it was planted, with very little if any other pruning done on it each year, so it is a remarkably low maintenance shrub. The bed where the Grevillea preissii subsp. gladrilimba grows has some soil contamination issues, as the northern end of the bed is where a septic tank was formerly located. This tank serviced the entire campus (or College as it was known in 1987), before the site was connected to the underground sewerage system in the mid-1980s. The septic tank, rather than being physically removed, had its top smashed in and it was then filled in with soil. Whatever chemical residue the septic tank contained then permeated into the surrounding soil, resulting in plant death in the first years after the bed was planted up in 1987. Even today, 35 years later, some of the original plants such as Thyptomene saxicola ‘F C Payne’ still show yellow, chlorotic foliage from whatever contamination persists. The Grevillea preissii subsp. glabrilimba, being at the far end of the bed where the septic tank was located, has shown no sign of being affected by this soil contamination.
Like many other of the coastal fringe plant species in the lower part of Western Australia, this grevillea can tolerate periodic waterlogging, often a feature of the sandy soils in the south west region of W.A. during the winter rainfall period. This is advantageous in cultivation, as this grevillea can survive on its own roots when grown out of its natural range, unlike like many other showy Western Australian grevilleas which have to grafted onto a compatible Grevillea species such as Grevillea rosmarinfolia, in order to survive on the eastern side of Australia.
Andrew’s Plant of the week…….16.07.21: Luculia gratissima
This week the plant I have selected, Luculia gratissima, is only part of the story I want to tell; I also want to mention the passing of Graeme Purdy, a frequent visitor and lover of the Gardens, who admired and requested I highlight this well-known winter flowering treasure. Graeme, for those of you who don’t know, wrote a weekly gardening column for the Herald Sun, for almost 30 years, and has also written several books on gardening. You name it, Graeme wrote about it, from growing pot plants to advising on pruning and vegetable growing, Graeme covered the lot. When we discussed the attributes of Luculia gratissima recently, I was quick to tell him that its flower display didn’t last long, and attempted to justify why I hadn’t, as yet, included it as the Plant of the Week. Graeme dismissed the short flowering period as being immaterial to the joy and fragrance the flowers bring to us in the depths of winter. He told me he greatly enjoyed having the flowers fill his senses when taking his regular walks throughout the Gardens. So, as a tribute to a talented, gentle horticulturist, I’ll savour the fine qualities this beautiful shrub has to offer, even if it is for just one month a year. It will give me something to remember Graeme by, each passing year.
Although this large shrub’s natural habitat is in forest margins from Nepal to Vietnam, its evergreen foliage (in our Melbourne climate) doesn’t seem to suffer from leaf scorching in Melbourne’s high summer temperatures, unlike one of the other Luculia species we have, L. grandifolia, that I wrote about last year. We have three specimens of L. gratissima in the Gardens: the original plant in the Wild Garden (southern end of the Orchard fence pathway), a second on the east side of the South island bed and a third specimen on the western side of the Bergenia Walk bed. The original specimen was well established more than 30 years ago, and the other two were planted a decade apart to ensure we continue to have specimens growing. As the fragrant blooms are borne on the ends of the previous Springs’ new growth, we prune the shrub back heavily after the flowers have finished, later this month.
This yearly hard pruning tends to reduce the size of the normally tall shrub to about two metres, which is about a third of what they would reach if left unpruned. The advantage of pruning heavily is that the flowers are lower down, so more easily seen, and their beautiful fragrance can be pulled down to admire. The other Luculia species we have, L. pinceana is similar to L. gratissima, but has a taller habit, a slightly different fragrance, and larger, more pleated, ruffled petals. In recent years many cultivars of Luculia gratissima have been introduced, with names such as ‘Pink Spice’, ‘Fragrant Cloud’ and ‘Early Dawn’. The cultivars seem to differ mostly in flower colour, which ranges from white, to pale shell pink, to a darker pink; what they all have in common, is the distinctive, complex fragrance..
The Latin name gratissima means “most pleasing” or “most agreeable”; the fragrance obviously made a big impression on Robert Sweet when he named the species in 1826.
Andrew’s Plant of the week…….07.07.21: Grevillea victoriae subsp. nivalis
As there seem to be so many grevilleas out in flower at this time of year, I thought I’d highlight one of the lesser known spider flowers, the Kosciuszko Grevillea, Grevillea victoriae subsp. nivalis. Grevillea victoriae was first described by Ferdinand von Mueller in 1855, and three subspecies are now recognised. The plant that von Mueller discovered was described as “12 feet” high, and was regal and imposing enough for him to name it after Queen Victoria herself.* Of the three subspecies, the latest, subsp. brindabella, was described in 2010, while subspecies nivalis, which we have in the Kath Deery Native Garden, was formally described and named in 2000, in an appendix to the Flora of Australia, well after Kath planted our specimen in 1986. Prior to naming, the subspecies had been known by botanists as ‘race d’, and was in cultivation for quite some time, often sold as Grevillea victoriae ‘Murray Queen’ or ‘Murray Valley Queen’. Like most of the plants Kath Deery selected for the Native Garden at Burnley in 1986, this grevillea would have been carefully chosen as an outstanding example of its species, because of its superior flower colour, foliage and form. This was the case with Kath’s choice of our specimen of Elaeocarpus reticulatus, which is a dark pink flowering for, rather than the usual white or pale pink colour that was commonly seen.
Grevillea victoriae and its subspecies are extremely cold tolerant, capable of growing above the snow line in the Australian Alps, (nivalis meaning snowy), due to the underside of the leaves being insulated with fine, felt-like hairs, called trichomes. G. victoriae subsp. nivalis has the greatest altitudinal range of them all, growing from 500 metres up to 1900 metres above sea level, primarily in the Kosciuszko National Park, situated on either side of the Victorian and NSW border. The foliage size can vary greatly, not only between plants but also on the same shrub, with leaves ranging from 20-135mm long to 7-37mm wide. The natural habitat is also varied, from rocky mountain slopes to acidic soils on creek margins, and it is well known as being drought tolerant once established. This subspecies, despite its wide altitudinal range, is currently regarded as endangered in the wild, most likely from habitat loss caused by clearing and grazing – a good reason to continue to propagate the specimen we have at Burnley.
Like all grevilleas, its main feature is its spectacular floral display, made even more interesting by their changing colour and form as the flowers mature. The flower starts out orange-coloured, the inflorescence resembling a bunch of grapes, and then changes to red as it matures, with the final form fully opening to the typical Grevillea flower. If you look carefully at the photo here of the fully opened flower, you can see nectar glistening in the sunlight. This nectar is extremely important to birds such as Eastern Spinebills and Yellow-faced Honeyeaters that feast on the constant supply of nectar produced throughout most of the year. It has been noted that once the flowers finish in January in the Kosciuszko National Park, the bird species leave the area to find an alternate food source. The species is not adapted to fire, so, like Mountain Ash it relies on seed to regenerate. In the garden situation, this means they don’t tolerate hard pruning, and need to be propagated from cuttings.
.*As you probably know, Queen Victoria herself was quite a small person.
Andrew’s Plant of the week…….01.07.21: Acacia flexifolia
This week I’ve realised I have been remiss in only featuring one acacia as a Plant of the Week in the past year. There are over 1000 Acacia species in Australia, with over half of them coming from Western Australia, and they are our largest genus of flowering plants. It is therefore appropriate that one of them, Acacia pycnantha, was chosen as our national floral emblem. Although we are some way off National Wattle Day, which is on the 1st of September, when we associate their yellow flowers with the start of spring, there are wattles flowering at any time of year, including the middle of winter.
The wattle I want to showcase this week is Acacia flexifolia, the Bent-leaf Wattle , a small, dense, drought tolerant species that occurs naturally in a narrow continuous band from Bendigo up to the Queensland border, in open eucalypt woodland. There are numerous situations where we search for a species to grow successfully beneath eucalypts, and selecting a species that naturally grows in such conditions gives us a good chance of success. The specimen we have at Burnley is growing under the large Eucalyptus tricarpa on the northern side of the Plant Science Lab. This is a challenging spot in which to establish vegetation, due in part I suspect to the allelopathic chemicals that the E. tricarpa is exuding from its roots to suppress understory vegetation, a strategy common in Eucalyptus species growing in drier situations, where moisture is critical to survival.
With such a large geographical range, there is great variation in the form and habit of the Bent-leaf Wattle. The glaucous (waxy bluish-green or pale grey) foliage of the form we have is probably one of the most preferred, and despite the species being described as low and spreading, the form we have at Burnley is more upright. The density of the foliage is a great attribute of this species and little pruning is needed to maintain the compact habit. At this time of year, from late May through to August or even October in some areas, this acacia is covered in bright yellow, fragrant, fluffy balls, with the tips of the tiny phyllodes sticking out like needles in a pin cushion. As this species only grows to 1.5-2 metres tall, achieved within 5 years, it is easy to include in most garden situations. Although the soils of its natural range tend to be shallow and rocky, it is highly adaptable, and grows in heavier clay soils that are periodically wet. Being an understory shrub, it is also tolerant of part shade, and can even flower successfully in shade. Like so many Australian plants, this Acacia species has adapted to fire and will regenerate and sucker, always an advantage to ensure it is a long lived plant species.
Andrew’s Plant of the week…….24.06.21: Heliotropium arborescens ‘White Lady’
This cultivar took my eye when I visited Heronswood in the early 2000s, where it impressed me with its shade tolerance, and its delightful vanilla fragrance. Although we already had the purple-foliaged, and purple- flowering Heliotropium arborescens ‘Lord Roberts’ growing in the Gardens, the white flowering form was renowned as being far more fragrant and shade tolerant than any of the purple flowering Heliotropium cultivars. While the “Cherry Pie” fragrance of the purple flowering forms is lovely, you do need to get up quite close to detect the perfume, whereas the white flowering form fills the surrounding air with a sweet fragrance that’s hard to miss. This is especially the case when the sun is out on warmer days, as the flowers seem to exude additional perfume that travels several metres, a particularly welcome attribute when this low shrub is planted next to paths or open windows.
The shrub grows to around 0.8 metre, lower in more shaded situations, and is one of those shrubs that you never know when to prune, as it always seems to be flowering. Being a sub-tropical shrub, it tends to keep on flowering if warm conditions persist, so at this time of year the flowering tends to diminish, and the colder weather results in the upper foliage becoming yellow and damaged. Although temperatures of minus 2 are noted as being its cold tolerance, our experience in the Gardens is that any temperatures below freezing severely damage the foliage, and even though frost doesn’t necessarily kill the plant, the leaves turn black and the lower shoots can be permanently damaged. Early spring is therefore a good time to prune the heliotrope back, so that any cold damaged foliage can be removed, and also to rejuvenate the shrub by encouraging growth buds lower down on the stems to grow. As the older stems tend not to have productive or dormant growth buds, it is best to prune back to the younger stems (1-2 year old wood), that already show emerging leaf buds.
Andrew’s Plant of the week…….18.06.21: Pittosporum multiflorum
This week we head down to the Rainforest Garden to feature Pittosporum multiflorum, the Orange Thorn. This compact, highly shade tolerant, prickly shrub was damaged in the storm last week, when a large cypress limb fell and snapped off several of the Orange Thorn’s branches. As it has taken 30 years to get to a mature size of 2 metres tall, it was disappointing to see this slow growing shrub damaged. Despite the fact that the natural habitat for this rainforest species is in wet gullies, the specimens we have planted under the dry shade of a two mature conifers (Cupressus macrocarpa and C. torulosa) have done remarkably well, although slower than the usual slow growth rate that occurs in wetter habitats.
The foliage of this shrub is very attractive, with its small, shiny leaves looking good all year round, with the bonus of new foliage tinged with a darker purple-red. However it’s the small, bright orange fruit during the winter months that holds the greatest attraction; it gives the impression of being a miniature citrus, and while its fruit are reported to be edible, most describe spitting it out due to its astringency. Birds however do find them palatable and the prickly nature of the foliage makes it a good choice for bird understory habitat.
This shrub is officially described as being dioecious, having female and male flowers on separate plants, although there is at least one report from Brisbane* of plants having bisexual flowers (flowers that have both female and male reproductive organs), and therefore self-pollinating. The summer flowers are very small, so difficult to inspect, and perhaps we are fortunate at Burnley that our three specimens have enough female and male flowers between them to enable pollination and fruit development. One of our three plants consistently has far fewer fruits than the other two, but the point is that they all have fruit, so while the species is considered dioecious, there aren’t distinctly male-only flowers on any one of our shrubs that are pollinating a female-only shrub. One possibility is that the pollen from one plant develops at a different time from the female part of the flower and therefore can only pollinate a separate shrub. The other possibility is that the flowers are truly bisexual. It’s a curious story and deserves to be investigated fully. There also seems great variability in the growth habit and leaf description of the Orange Thorn, with some sites reporting a suckering habit and the Canberra Botanic Gardens (Australian National Botanic Gardens) describing it as ‘rapidly expanding in the forest gully’, without stating whether this was by seed or suckering. Certainly at Burnley, none of the seed germinates, and the plants don’t sucker.
The species has a large geographic range, growing from just above Bega in New South Wales to southern Queensland, and is found in the dense, shaded understory on the margins of coastal and hinterland rainforests. The specimens we have at Burnley were part of the original plantings of Phil Tulk’s** design that I mentioned previously when highlighting Tripladenia cunninghamii, another extremely shade tolerant species used in the understory of Burnley’s Rainforest Garden.
There is also a story in the species’ former name, Citriobatus pauciflorus, pauciflorus meaning few flowers, as its name was intended for another species entirely that was described from a fossil specimen. The updated name, Pittosporum multiflorum has now been accepted, although it is acknowledged that the species name multiflorum, which means many flowers, isn’t representative of the plants’ flowering habit. Strange to have a specific name that doesn’t describe the plant.
**Gardens Manager 1987-2001
PS Don’t forget to click on the pictures for a bigger view.
Andrew’s Plant of the week…….10.06.21: Gladiolus dalenii
This week I bring some dazzling colour to our cold winter by showcasing Gladiolus dalenii, the Parrot Gladiolus. This well-known bulb (technically a corm) has an incredible habitat range and distribution, almost the entire African continent, in open grassland, woodland, rock savanna, mountains, and among rocks next to water courses. This gladiolus is notable as being one of the few that is edible. When I say edible, the high protein and carbohydrate rich corms need to be carefully prepared by boiling them first, followed by leaching them in water for several days. The corms are also used for numerous medicinal remedies, such as treating colic, dysentery, making poultices and treating snake bites, stings, and insect bites.
This gladiolus is also one of the parents of the original crosses that led to the large-flowered hybrids we have today in the cut-flower industry and used in gardens. One interesting feature of the hybrids is that they will flower 90-100 days after planting out, so it’s possible to time the flowering period, which is very beneficial to the cut flower trade. Dame Edna Everage made them a household name when declaring they were her favorite flower, never being without a bunch on stage or in publicity shots.
On the African continent, Gladiolus dalenii is considered a summer flowering species, with its flowering connected to the start of the rainy season, which varies in different regions, so flowering can occur from December through to May. The three subspecies are also known to flower sporadically throughout the year, depending on the timing of moisture, and are highly variable in flower colour, depending on which region or country they come from, with pure yellow, dark red, orange, and a combination of all these with brown markings all possible.
It’s thought that the scarlet orange with the yellow throat variation we have at Burnley comes from South Africa, as it’s known to flower later than other Gladiolus dalenii, in April, May and June. This splash of colour is very welcome during early winter, and they look spectacular planted in groups or long drifts. They do need support, less so than the new hybrids that need tying to a stake, but to reach their full display potential, the tall flower spikes are best supported to stop them falling over. Rats have also been known to eat the corms, and to make matters worse, often just when the flowers are beginning to bloom. The corms can be planted and left undisturbed, and apart from staking, the only other maintenance required is cutting the dead foliage down in late spring.
Andrew’s Plant of the week…….3.06.21: Bowkeria verticillata
This week’s plant is rather a mystery, as although I know what it is, I have no idea where it came from or indeed how it got here. I first noticed this multi-stemmed shrub in early 2017, growing in the shade under the large Ficus obliqua in the Azalea Lawn area. It’s not uncommon for plants to self-seed in the Gardens, or so I thought, so I set about identifying it. I was surprised to discover it was Bowkeria verticillata, the Natal Shell-flower Bush, one of a genus of only three species that comes from the forest edges of the Eastern Cape in South Africa. Once I’d identified it, I realised that its tiny seeds would be highly unlikely to be distributed by birds, so I can’t explain how it came to be growing out of the dense ground cover layer of chlorophytum (Spider Plant) under the fig. The Royal Melbourne Botanic Gardens have a specimen in their South African section and according to Tim Entwisle’s 2018 blog, the seed capsules he observed failed to set any fruit. Perhaps this has changed since then.
What’s interesting is that Tim’s flower at RBGM didn’t have the characteristic “pattern of red marks” on the inside of the flower that are referred to elsewhere as being a possible guide for pollinators to the flowers’ oil-bearing hairs. In South Africa, the pollinator is an oil-collecting bee, Rediviva rufocincta, that has specialised setae or bristles on its forelegs that collect the oil, and transfer it to its hindlegs, from where it is carried back to the hive to feed the bee’s larvae. As this bee is endemic (only found) to South Africa, something else must be pollinating the Burnley specimen, as there is plenty of fine seed within the capsules that I have shaken out. The flower is pure white, with an odd twisted shape to the top part of the flower that stops you seeing what’s inside. The fragrance is a bit odd too, it is meant to be fragrant and lemony, but you have to get up really close to detect any odour, and to me, it has an oily smell. The foliage is also intriguing, as the leaves are in whorls of three around the stem, giving the branches a full, 3-D appearance. The dark green leaves have a distinctive purple-red mid vein and are soft and felt-like to touch. The references I’ve read for this plant describe it as slow growing, up to 50cm a year; 50cm doesn’t sound slow to me, and in the last four years the specimen growing in the shade at Burnley has grown from about 1.8 metres to 4.5 metres, so about the expected growth rate .
The Burnley specimen isn’t something spectacular, the flowers are sparse, and the straggly habit under the canopy of the fig seems typical of a plant that would benefit from more sunlight. It is reported to be reliant on ample moisture, so not drought tolerant, which makes sense, given its natural habitat along watercourses, but as I’ve highlighted previously, sometimes plants surprise us with their tolerances outside of their natural habitat. The other two species in the genus, B. cymosa (with showy panicles of white flowers) and B. citrina (with yellow flowers) both seem to have more interesting flowers and foliage than B. verticillata. The genus was named after amateur botanist Mary Barber (nee Bowker), and her family by William Harvey, who was put in charge of the Trinity College Herbarium in Dublin. William and Mary were in regular correspondence for a number of years in the mid-1800s, discussing and identifying the Eastern Cape flora in South Africa, particularly after Harvey’s publication of his book, The Genera of South African Plants: Arranged According to the Natural System that Mary was able to use for her nature studies.
Andrew’s Plant of the week…….27.05.21: Vitex lucens
This week I’m featuring an ornamental, remarkably resilient and long-lived tree, Vitex lucens, the New Zealand Puriri Tree. The species is endemic to the top half of North Island, where it once grew in fertile coastal forests. The tree was extensively logged by European settlers for its durable and incredibly hard, structurally strong timber, which was used for a multitude of applications, such as fence posts, bridges, railway sleepers, firewood, building foundations, and, incredibly, even engine bearings and gears. The timber is so durable that fence posts inserted in the ground more than 100 years ago are still intact and free of wood rot, and the timber is so dense a special ‘Puriri Stapler’ had to be invented to attach the fencing wire to the posts, as the regular stapler couldn’t penetrate the wood. In the region of the North Island known as Northland, there are old water pumps that still operate on bearings made from Puriri timber. The secret of its strength and durability is the cross-grain structure of the wood and the yellow tannin, that is also used as a dye. The timber is so dense that it sinks in water, which is the reason it was used to make eel traps.
Although you might get the impression if visiting the remaining trees in New Zealand that their natural habit is to grow in a twisted, gnarled shape, there were in fact 20 metre tall, straight specimens selected for timber harvesting, which just left the ungainly, un-wanted specimens found today in farm paddocks. The fertile volcanic forests where the trees grew were cleared by Europeans for agriculture, mainly for animal pasture and cropping. Damage from burning, cutting down and root upheaval seems to have no serious impact on the species, with damaged trees re-spouting and continuing to grow. The species lives to an incredible age, with one surviving specimen estimated to be 2000 years old, much older than the first arrival of humans in New Zealand.
The tree has great cultural and medicinal significance to Maori people, with its name incorporated into a welcome greeting, used in burial practices, and an infusion of the leaves used medicinally for sore throats, joint pain, sprains and to cure ulcers. In New Zealand the tree is also an important source of food for birds, as the nectar-rich flowers and abundant bright red fruit (a drupe) are both present throughout the year. The red flower colour is unusual for New Zealand plant species, with most flowers being white or green.
Of interest also is the heat resistance of the ornamental, shiny, palmate leaves, that aren’t damaged by the high temperatures of Australian summers, unlike the foliage of Corynocarpus laevigatus, another New Zealand tree species we have at Burnley, that scorches and blisters in the 40 degree°+ summer temperatures that we’ve experienced a few times in the last decade.
The bright red fruit of Vitex lucens, that look like round cherries hanging below the foliage, are a wonderful, long lasting feature of the tree, as are the red summer and autumn flowers that carpet the ground underneath. I’m unsure how old the specimen near the Rose Garden – Oak Lawn arbor is at Burnley, as there is no reference to the tree in the 2002 Conservation Management Analysis (CMA). I suspect it was planted over 100 years ago, as there are other nearby plant specimens, such as the Boehmeria nivea (Chinese Silk Plant), mentioned in the CMA, as being planted in Bogue Luffmann’s time (the First Principal of Burnley 1897-1907).
Andrew’s Plant of the week…….20.05.21: Tagetes lemmonii
I suspect most Melbourne gardeners think of marigolds as low growing annuals, but of the 56 species, 26 are perennials, with the best known of the three commonly grown perennial species being the tallest of the genus, Tagetes lemmonii. As is often the case, there are numerous common names for this marigold, including Tree Marigold, Lemmon’s Marigold, Tangerine Marigold, and Copper Canyon Daisy, with Mexican Marigold, referring to its origin in the higher mountain ranges in Northern Mexico perhaps the most frequently used in Australia. This Tagetes species was named after the botanist Sara Lemmon and her husband John, who discovered it in 1880 while camping on their honeymoon in the Arizona mountains.
While we tend to assume this 1.8-2.4 metre shrub has good drought tolerance, its natural habitat is in moist sites beside streams, and in woodlands, canyons and mountain grassland, at altitudes of from 1400 to 2500 metres. The mountain range where it grows has two wet seasons, a monsoonal summer (with the majority of the rainfall), a wet winter, and a drier autumn and spring. So once again, we have a plant that surprises us with its tolerance of the conditions we grow it in, which are so different from the natural conditions of its origins.
Like all Marigolds, the Mexican Marigold has pungent foliage, and can be used as companion planting for the plants of the nightshade family of tomatoes, capsicums, eggplants and their relatives, where it is known to control soil nematodes and leaf sucking insects. Depending on your sense of smell, the pungent oil in the finely divided pinnate foliage has been described as a combination of passionfruit, lemon, mint, and mandarin, or a dominance of one of these.
Although this marigold has pest controlling and medicinal properties (mild anti-inflammatory and analgesic properties for upper intestine irritation), it is the long flowering period, lasting up to 8 months, that makes this shrub so rewarding in gardens and the broader landscape. The darker yellow to orange flower colour looks wonderfully warm in the winter season, especially when the sun is out to make them glow.
There is a fair bit of choice in yellow, winter-flowering, compact shrubs, with the South African daisy bushes Euryops pectinatus and E. chrysanthemoides giving some stiff competition to the Mexican daisy. While both Tagetes and Euryops have the same floral impact of a dense canopy coverage and a long flowering season, it’s the Tagetes’ response to pruning that tends to sway me in its favour. Like all good things, they have to come to the end, so eventually both Tagetes and Euryops need an annual or occasionally more severe prune after flowering to maintain a compact habit, and to develop the terminal flowering wood for next year’s flowers. In the case of Tagetes, the fast-growing stems tend to fall away from each other, but unlike the Euryops species, there is abundant regrowth on the lower stems, so Tagetes after pruning still looks green and pleasant.
Although often regarded as short lived, if annual pruning is undertaken to regenerate and stimulate younger stem growth, Tagetes lemmonii can be long lived. In fact, the specimen we have at the lower end of the Oak Lawn was planted more than 20 years ago, and is still growing and flowering well. If given open soil conditions, this Tagetes species, like so many other members of the Asteraceae (the daisies), will self-sow near the parent plant, although I find that while Euryops specimens tend to have seedlings carpeting the ground, there are just a few around Tagetes lemmonii in the Swan Street planting, and the Oak Lawn specimen has no self-seeding issue, likely due to the dense cover of Liriope muscari, which provides no opportunity for seeds to germinate and survive.
Andrew’s Plant of the week…….12.05.21: Buckinghamia celcissima
This week we head down to the Rainforest Garden to admire the Ivory Curl Flower, Buckinghamia celsissima . It certainly lives up to its common name, with the intricate curly inflorescence looking rather like Mr Curly from a Leunig cartoon. This tree’s natural habitat is the rainforests of North Queensland, where it grows to 30 metres to emerge out of the rainforest canopy, however in southern regions it is either a small tree to 7 metres or a large shrub, like the plants we have at Burnley. The two specimens in the Rainforest are part of the original 1990s plantings of the very successful design done by former Garden Manager Phil Tulk. While the Davidson’s Plum (Davidsonia pruriens) that was also planted failed to overcome the colder Melbourne conditions, the Ivory Curl has survived well, flowering each year for many months.
This small tree is reasonably common as a street tree throughout Brisbane and in southern areas, apart from frost prone climates such as Canberra. Relatively slow growing at Burnley, I’m sure it will perform far better in other situations not limited by the root competition, shade and southern aspect of the Rainforest at Burnley.
P.S. Can readers recognise the Ivory Curl Tree as a member of the Protea Family? Its flowers are quite similar to those of another rainforest tree, the well known Macadamia, which can also grow well in Victoria.
Andrew’s Plant of the week…….06.05.21: Hibiscus rosa-sinensis
This week is the first anniversary of Plant of the Week, and rather unusually, I’m hoping someone can identify one of the two plants featured, as although we know the genus and species, and the cultivar name of the double-flowered Hibiscus rosa-chinensis ‘Mrs George Davis’, we don’t know the cultivar name of the salmon coloured, single-flowered hibiscus next to it. It seems that Hibiscus rosa-sinensis is unknown in the wild, with all of the many cultivars apparently hybridized or bred. The origin of this breeding program is thought to be India, from whence they were exported and further bred in China, and then across the Pacific. Breeding really took off in the early 19th century, and it’s estimated that sixty percent of the cultivars bred in this early period no longer exist. However, hibiscus breeding continues apace, with the enormous number of cultivars in existence, and the many new cultivars being produced in recent years far outnumbering the others that are now lost.
The plant name is only part of the story this week though: the main thing I want to highlight is where the two shrubs are growing, on the north side of the 1970s Student Amenity Building, under the eaves where they get no supplementary irrigation or natural rainfall. How they survive in this narrow bed is testimony to the extreme conditions that plants can adapt to. With a concrete slab and brick wall at the rear and asphalt in front of the narrow bed, it seems an impossible place in which to grow plants, apart perhaps from cacti. The secret to their survival here can perhaps be explained by something Dr Moore once told us: asphalt is a water and air-porous material that allows roots to survive under its surface. When you think about the trees planted in little car park beds you can see the same outcome: there would be no way in which a tiny round bed surrounding a tree in a car park could sustain its growth, unless the roots could harvest the necessary air and water through the asphalt surface.
Of interest also with these two hibiscus cultivars growing side by side, is the aphid resistance of one and the high susceptibility of the other. The single, salmon-coloured cultivar has none, and the double pink cultivar ‘Mrs George Davis’ is covered in them, a regular occurrence each year.
Apart from an annual clip and very occasional hard prune to allow bike access, these espaliered hibiscus provide a fantastic floral display under hostile conditions, an amazing feat that defies our beliefs of the conditions in which it’s possible for plants to survive and flourish.
Andrew’s Plant of the week…….28.04.21: Euonymus alatus
This week it seems very topical to include an autumn foliage plant, as I’m sure most of you are surrounded by colourful trees and shrubs in your own gardens and others that you visit. While Burnley Gardens isn’t as spectacular as some you will see in Bright or the Dandenongs, it does have a selection of trees and shrubs that provide great delight. Just this week the student’s plant identification list was dedicated to autumn foliage trees, with the multi-coloured Parrotia persica, and Pyrus calleryana down in the quadrangle being two of the trees they are to learn.
The autumn colouring of many shrubs in the Gardens also brings some visual impact, and one that always takes my eye at this time of year is the aptly named Burning Bush, Winged Euonymus, or Winged Spindle, Euonymus alatus. Introduced to the Gardens in the early 1990s by Gardens Manager Phil Tulk, this multi-stemmed shrub has what I consider all-year interest, an important factor in selecting a plant for a congested landscape like Burnley’s, where plants need to justify their existence, demonstrate their qualities, in order to be selected. In the case of this Euonymus, the all year-round attributes not only include the spectacular, fiery red autumn foliage, but also colourful fleshy seeds and ornamental corky-winged stems that become quite prominent once the deciduous autumn foliage has fallen.
Although most seem to think the flowers are insignificant or inconspicuous, I find them rather delicate and interesting, as they are well displayed on the branches, and are a lighter greenish colour that contrasts attractively with the bright green new spring foliage. So, there is interest in every season. This is a slow-growing compact shrub that needs little if any maintenance, and it is adaptable to part shade situations as well as brighter sites. There is a compact form named ‘Compactus’, but we are not sure if our specimens are that cultivar, as they appear to be naturally slow in our conditions in Melbourne. It’s interesting that this species has become such a dreadful weed in 21 American states, where the small ornamental red fleshy seeds either readily germinate under the plants to from thickets, or are spread further afield by birds. From what I can gather, the seed need a month or two of cold stratification to break the seed dormancy to enable germination, so Melbourne probably never gets cold enough for long enough for the seeds to germinate. It certainly never self-sows in the Gardens at Burnley but perhaps it’s a different story elsewhere. The only other factor that might stop its selection is the slow growth rate, however as a massed planting in the foreground of a garden bed, or as a single specimen, it quietly gets on with growing without excessive irrigation or fuss.
Andrew’s Plant of the week…….21.04.21: Haemanthus coccineus
This week I’m highlighting the berries, rather than the flowers of Haemanthus coccineus, which has recently finished flowering. The berries are beautiful, slightly elongated and multi coloured that remind me of precious jewels or old fashioned jube lollies. Unfortunately, the fleshy colourful coating around the seed isn’t edible, and interestingly isn’t eaten by animals or birds either. This South African bulb has a few common names (a familiar occurrence with plant names that I’ve mentioned previously) including Blood Lily and Paint Brush Lily, a rather apt name, as the flower does look like a stubby paint brush. For me, despite my tendency to admire orange flowers, the flower of Haemanthus coccineus is a little too odd and brash for my admiration. The speckled flower stalks are interesting, just like the unusual flower, and it certainly captures people’s attention as they walk past them in the Kirkhope rockery, often stopping to take a photo of the slightly bizarre protrusion coming out of the bare soil. Like many South African bulbs, Haemanthus coccineus has developed a survival strategy of withholding their leaves until the autumn rainfall occurs, after the dry summer. The flowers are first to emerge from the summer dormant bulb, enabling them to be pollinated and set seed to take advantage of the cooler, wetter conditions that will maximise the growth potential of the seedlings before another hot, dry summer arrives. This is the case with the Blood Lily: the seed has a short viability period, as delaying germination would only ensure a shorter growth period before summer dormancy occurs again.
The generic name Haemanthus is from the Greek word for blood (haima) and flower (anthos), while the specific epithet coccineus is Latin for scarlet, or red, so you may well ask why a bright orange flowering bulb has such botanical names associated with it. The answer can be found in the huge area of South Africa where this bulb grows, as well as the wide range of habitats, from the coastal fynbos, that I mentioned last year, to the top of the 1200 metre Table Mountain. This wide range of habitats and geographic locations has resulted in a large variation in flower colour, with the first recorded specimen taken from Table Mountain in Cape Town by a Flemish botanist in 1605 obviously far redder than the bulbs I’ve seen in Australia. Looking online at overseas specimens, you can see photos of bright red flowers from the same species so it would be interesting to hear if anyone has the red flower colour in Australia.
Note: what appear to be solitary flowers are actually dense heads of small flowers, surrounded by red or orange bracts or spathes. And don’t forget to click on the pics to see a bigger version.
Andrew’s Plant of the week…….14.04.21: Physalis alkekengi var. franchetii
This week we head down once again to the Orange Purple Border, just inside the ornamental Field Station gates, to highlight a highly ornamental and scientifically interesting sub-shrub, Physalis alkekengi var. franchetii, the Chinese Lantern. Like many plants, Physalis has numerous common names and as many of you would associate Chinese Lantern with the genius Abutilon, perhaps one of its other common names could better represent it’s qualities, such as Bladder Cherry, Winter Cherry or Japanese Lantern. All these common names give some insight into how it is used (the common name Bladder Cherry referred to its use as a remedy for bladder problems), when to expect a display and where it is used and grows. Japanese markets are known to sell long stems of the colourful lanterns for indoor floral arrangements.
I got this specimen from an Irish lass, Moira, while visiting Canberra in winter time. I was smitten by a dried indoor floral display in her kitchen, and promptly requested some of the dormant runners be dug up to take back to Burnley. They were given to me with a cautionary tale: contain its spread, or you will regret its invasion for ever more.
I therefore planted the root pieces in two sunken half tubs and provided a metal pyramid for them to grow within. Pretty much a prison below and prison bars above, not the most welcoming environment, but as James Hitchmough would have relegated it into the ‘thug’ category, I took no chances with it escaping its confinement. The first year of its growth was resplendent, with masses of eye-catching orange lanterns tumbling through the metal bars. Some of these I harvested and hung up in my office window, where people entering reception could appreciate the brilliant display. The remainder I cut off and hung upside down on the metal pyramid to provide an outdoor dried floral display. Being herbaceous, the foliage and stems die off during the winter, so you need to harvest the colourful fruit calyces when they are at their peak, around this time of year. Also at this time of year slugs are gleefully devouring the orange calyx, which is very poisonous to us, leaving an ornamental, delicate lace mesh casing around the bright orange berry (edible but rather nasty tasting) within.
There are two recognised varieties of Physalis alkekengi; the one we have is the more desirable larger-fruiting form, with glabrous foliage, which is common throughout China. It has been found in Siberian fossils up to 23 million years old, and has a long association with Chinese traditional medicine. Physalis alkekengi var. franchetii has 124 chemical ingredients in different parts of the plant, with the steroidal physalins and flavonoids being some of the most important and potentially beneficial for medical research. The species has a wide range of medicinal uses, especially in Chinese traditional medicine, primarily for its anti-inflammatory properties, as well as reducing and preventing coughs and loosening mucus, reducing fevers, dissolving kidney stones, aiding in urinary tract infections, as a laxative and to treat skin diseases. All these traditional remedies have led to intense research in the last few decades, with many studies done at the University of Melbourne and other parts of the world.
Of course as horticulturists, we are more focused on its ornamental qualities, and like Lunaria annua (Honesty) or Xerochrysum viscosum (Sticky Everlasting), which are also marvellous dried floral plants for indoor decoration, Physalis will provide a long lasting and cheerful display for the long winter season.
Andrew’s Plant of the week…….06.04.21: Apios americana
This week I’m relating a rather curious event, the sudden, un-planted appearance of Apios americana, American groundnut, on the fence line at the ornamental gates into the Field Station. Although this is one of Chris Williams’ food species planted further down in the Field station, Chris has never noticed it setting seed (although it has edible pods), in fact some plants sold are considered sterile, so it’s sudden appearance is curious. No matter how it got there, the abundance of closely packed pea flowers, with their distinctive crimson-red colour variation (and fragrance), make it highly ornamental. Unfortunately, the underground edible tubers are rather persistent and invasive, so I won’t be able to leave it in its current location, as the last thing I need is an underground invader.
This plant is well suited to wetter soils; it’s natural habitat is riparian (growing near water) areas of eastern America, however like many plants with underground storage adaptations, Apios can survive with less moisture. A vine that grows to several metres, the tubers (botanically a rhizomatous stem) are great eating, and have a protein content three times that of potatoes. The flesh is pure white and needs to be cooked to be edible. It’s reported to taste like a yam (Dioscoria , another of Chris’s plants), with a texture of cooked turnip. Chris recommends it be boiled rather than baked in the oven, unless you want to make flour out of it, which is also possible. Once boiled, which removes the bitter latex, the tubers can also be fried up with other culinary delicacies. A little patience is required for harvesting larger sized tubers, as it takes a couple of years to get them bigger than the size of a walnut.
This is one of Chris William’s classic edible plants, good to eat and highly ornamental, worthy of growing for its flowers alone…or as something to eat; take your pick (but be mindful of those persistent tubers).
Andrew’s Plant of the week…….31.03.21: Cydonia oblonga
This small tree is growing at the bottom of the old orchard and is one of the last remaining trees planted after the 1934 flood. This flood wiped out many of the mature fruit trees in the orchard, pushing many of the trees sideways out of the ground, which then necessitated a re-planting of the orchard trees. The existing two rows of pear trees further up, and the Mulberry opposite them are the only other remaining trees from the former orchard. All the other trees were removed in the late 1980s when the area was re-purposed as research station and renamed as the Field Station.
The wetter season this year has been a great boon to the size of the fruit this quince has produced, with many of the quinces being 15cm long and 10cm wide, far bigger than previous crops in this un-irrigated lawn area below the veggie plots. Until recently, the tree was un-netted, which meant people would be more tempted to jump the fence and harvest the lot, or the birds would damage them. The last few years has seen Rowan from the Nursery take a great interest in this old specimen, which has resulted in the tree being netted and the fruit harvested and distributed to Burnley staff and students. There is even a fun Quince Appreciation Society (QAS) that has been created to share the joy of quince paste, slow poached quinces or just taking a few quinces home to cook.
As you can see from the photo I’ve taken of the trunk, the tree has seen better days but its height and width lends itself well to being easily harvested and netted and it’s great the tree continues to produce such an abundant crop each year. I’ve asked the nursery to propagate the tree this year, so that we don’t lose this un-named cultivar from Burnley’s folklore.
Dont forget to click on the pics for a bigger view.
Andrew’s Plant of the week…….25.03.21: Ampelopsis glandulosa var. brevipedunculata
This week a plant that has caught my attention is the Porcelain Berry, Ampelopsis glandulosa var. brevipedunculata. This pretty climber is another plant for which there have been a number of names over the years. Most of us would have either known or been taught this plant as A. brevipedunculata, in fact just this week a new batch of students were walking around the Gardens, as I did 25-30 years ago, wondering how to remember such a long name. Well, the name just got longer with the addition of glandulosa in an already long name.
I was so impressed with the amazingly colourful berries of this plant all those years ago that I planted one at home, in a pot with a westerly aspect, only for it fail to produce the same prolific berry clusters I knew it was capable of. We have three specimens at Burnley, plus a variegated form, A. glandulosa var. heterophylla, more commonly known as A. brevipedunculata ‘Elegans’, but which may also be known as Ampelopsis glandulosa f. elegans, Ampelopsis glandulosa var. brevipedunculata ‘Elegans’, in fact A. glandulosa var. heterophylla has no less than 19 synonyms! Is it a cultivar, or a botanical variety, or a form? It’s all a bit of a mess really! It’s interesting to note that the Kew herbarium lists the native range of the variety heterophylla as far east southern Russia to China, S. Sakhalin to Japan, while var. bevipedunculata has a native range of Russian Far East to Korea.
Whatever its name, it is less vigorous than the green form, but only one of the specimens planted has an abundant berry display this year. The oldest specimens in the gardens have been growing in the same place for decades, on the lattice fence between the blue and red orchard border colour beds; it was in fact the very specimen I was taught in plant ID. The second specimen is a self-sown plant, fighting it out with a honeysuckle (Lonicera japonica) in one of the student gardens. It’s the third specimen, in the orange-purple border inside the orchard gates that has such a colourful berry display. It must be the wetter season this summer, as the foliage growth and berry production are outstanding. I can see why it was introduced to the east coast of America in the 1870s as a ground cover, as the area it has covered since spring is about 6 square metres2, quite prolific. On the east coast of America, A. glandulosa var. brevipedunculata is considered a terrible weed, climbing to 8 metres high, a height not attained in Australia, and smothering trees.
This vigour was one reason for its selection as one of the climbers for a research trial into climber growth in recent years in the Field Station. What interested me when seeing it trained onto a vertical structure was the V-shaped growth habit it exhibited. It led me to believe that if I was to grow it as a screen, it would end up with gaps between each plant, unless they were planted close together or the lower tendrils were trained. I’m rather partial to using vines as ground covers, with my two stand out plants being Trachelospermum jasminoides and Clematis microphylla, both of which provide a dense cover, even in shade.
The reason for this Ampelopsis species’ spectacular range of berry colours makes an interesting story. It’s to do with changes in the pH of the fruit. As it ripens from green to white, to pink, light blue, dark blue to purple, the pH rises from acidic to alkaline, something we would normally associate with the soil pH of hydrangeas when determining their flower colour (acid = blue, pink = alkaline). However, with the Porcelain Berry, it’s all happening independently of soil conditions, occurring because of the interaction of anthocyanins and flavonols. Anthocyanins are a common colour pigmentation in plants that react to changes in pH, and the colourless compounds of the flavonols bond with the anthocyanins to produce the co-pigmentation that make this berry so special.
On closer inspection, the berries have speckling on them, making them look like miniature bird eggs or little porcelain beads (hence the common name).
Would I recommend growing this plant? Probably not. It seems a bit fickle with its berry display, one of the key reasons to plant it, and the fact that it has self-sown could be an indication that the bumper crop of berries this year may mean un-wanted plants in places where birds have visited. The variegated variety of the species (A. glandulosa var. heterophylla (‘Elegans’) is the more manageable form to grow; the new spring foliage has interesting pink tones and the summer foliage has a pleasant light green appearance from the subtle leaf variegation. But don’t expect a full berry display every year, it seems to be elusive.
Correction. Please note: when first published, we had the pH colours in this article the wrong way round. (acid = pink, blue = alkaline). The error was pointed out by Graham Purdy, the now retired weekly garden writer for the Herald Sun. Thank you for being on the ball Graham, and for letting us know.
Andrew’s Plant of the week…….18.03.21: Quercus bicolor
This week I’m highlighting an oak tree, Quercus bicolor, the White Swamp Oak. Reasonably common in larger public gardens and in streetscapes throughout southern Australia, this large, long lived, deciduous tree has a good broad canopy that makes a great shade tree. The specimen we have at Burnley, opposite the Library, was planted in 2005 and is living up to its reputation as being fast growing. Despite its common name perhaps suggesting it requires permanent inundation, the tree in fact only tolerates periodic waterlogged soils, and conversely, is also renowned as being surprisingly drought tolerant. It’s also tolerant of temperature variation, capable of coping with temperatures well bel
ow freezing, as well as 40 degrees. This reputation is probably why it has been used as a street tree in Canberra. Normally you would think that fast growing trees wouldn’t be long lived but in north east America where this oak species grows, it can live to be 300 years old. That was one of the reasons I selected it as a specimen for the Gardens, as it was replacing an Acer negundo (a variegated form), a notoriously short-lived tree, that had begun to fall apart from decay.
20 years ago when I became the Gardens Manager of Burnley, there were only five species of Quercus growing, two of them considered significant: the National Trust-listed Cork Oak and the Heritage listed English Oak. Three are evergreen, something we tend not to associate with oaks, as most of the over 600 species are deciduous. Part of my tree planting over the last two decades has been to increase species numbers within genera, as well as to introduce new genera we didn’t have. The result is that we now have ten new species of oak, plus a fastigiated Q. robur cultivar, and I’ve also planted future replacement trees of the Cork Oak and the English Oak, to ensure continuity. I’ve done a rough count of how many trees have been planted in the last 20 years, and its more than 140 (out of a total of about 830). About a third of those make up mass planting of a single species, such as the Corymbia citriodora avenue in the Lagoon Paddock, and the remainder are either new genera or increasing species within a genus, such as Araucaria, Agathis, Brachychiton, Flindersia and Quercus.
Trees are an important factor in large gardens, so bulking up tree numbers will provide a desirable future asset, while future and current climate suitability has been a key driver to my tree selection. The eight new Agathis and three new Araucaria species planted within the north-south axis of trees, from the existing National Trust listed A. robusta on the northern end, to the new A. silbae at the Rose Garden on the southern end, will I hope maintain what we refer to as the “Burnley skyline”: the band of trees along the western fringe of the Field station fence line.
Andrew’s Plant of the week…….11.03.21: Tibouchina urvilleana
To use a catch-cry from famous Australian cricket commentator Bill Lawry, “It’s all happening!” in the Gardens this month. So much to choose from, with plenty of show-stoppers demanding our attention. I thought I’d better start with a follow up photo of Crataegus tanacetifolia, which I mentioned in early November, as the abundant fruit is causing a great deal of interest and comment. The wetter season has really plumped-out the brightly coloured edible fruit so not surprising it has taken everyone’s attention.
Also capturing our attention is the Tibouchina urvilleana or nearby Tibouchina ‘Groovy Baby’ in the colour theme borders near the Field Station gates. Tibouchina has several common names, including Lasiandra, a previous name of the genus, Glory Bush and more recently referred to as Princess Flower, which seems appropriate, given its royal purple hue. This is one of my fall-in-love plants, as the iridescent royal purple flowers remind me of a visit to Thailand, where purple is the colour of her royal highness Princess Sirindhorn; these flowers would make any Thai person proud. This plant can either be a noxious weed or thing of beauty, depending on where it’s grown in the world. Originating from tropical rain forests of Southern Brazil, it has naturalised in many places, including New Zealand, Hawaii, the Pacific Islands and Jamaica, where it has escaped gardens, and is now considered an environmentally noxious weed. Hard to imagine in a climate like Melbourne or even slightly further north, but given higher rainfall, this small scrambling tree or large shrub can sucker and form dense thickets. It seems to need more than 60mm per month of rainfall and minimum temperatures above 3°C to become a weed problem, but this is easily achieved in sub-tropical, let alone tropical zones. Introduced to Australia in 1938, it’s mostly used as a feature plant or hedge, but can be trained onto a structure, or espaliered to form a vertical or screening display. Given the right warmth and moisture it will flower continually throughout the year.
There is some hope of a biological control of Tibouchina urvilleana in areas where it is considered a noxious weed with a eucalyptus pathogen Holocryphia eucalypti, which is significantly more virulent on T. urvilleana, where it attacks the stems, than it is on Eucalyptus species. Work is also being done with a Colombian fungus Chrysoporthe cubensis, a leaf spot pathogen in China, and a root rot (Pythium sp.) in Taiwan.
Some Queensland plant breeding in the last decade has introduced a range of dwarf cultivars, including T. organensis x mutabilis, which has been named ‘Groovy Baby’, a name made famous in the publicity of the Austin Power movies. For those interested, ‘Groovy Baby’ means even more groovy than groovy, the grooviest! Although this dwarf plant can look a bit pretentious, with the small foliage looking out of scale to the enormous flowers, I just can’t resist the look of the flowers smothering the whole shrub, to the extent that you can’t even see the foliage. The leaves of ‘Groovy Baby’ aren’t quite as spectacular as those of T. urvilleana, which has larger leaves with more prominent hairs, and both have dramatic red markings on the flower buds, which all combine to make members of this genus very attractive shrubs.
Andrew’s Plant of the week…….05.03.21: Cochliasanthus caracalla
This week’s plant, Cochliasanthus caracalla, Snail Vine, is a lovely, fragrant climber. Burnley has two specimens, one outside Reception, and the other on the fence near the Ornamental Gates to the Field station, both relatively newly planted. The specimen outside reception replaced the Wisteria floribunda that Geoff Olive had planted in the late 1970s, and although I felt rather guilty in removing it as part of the re-development for the ramp installation in 2013, training the Wisteria in the small space available just resulted in it escaping onto the roof, rather than growing where it was intended. I digress slightly, but it’s worth noting that we have two Wisteria specimens trained as large, round balls, which behave nicely, in terms of needing little containing; the remaining specimens are trained onto overhead structures and managing them tends to be like herding cats, not an easy gig.
So once I got over feeling guilty for removing Geoff’s wisteria, on practical grounds, my plant selection thoughts led me to the Snail Vine, as it is fast growing, has fragrant flowers and more importantly, flowers in late summer to early autumn, on last spring’s growth. This was important, as it meant we could heavily prune the rampant growth in early spring, containing it to a small vertical space, and still get good flower production soon after. Keep in mind that Wisteria species flower on two year old growth, while Cochliasanthus flowers on new growth.
Having decided on the plant, I then bought a Snail Vine from a nursery, only to discover that there may be more than one plant with the same common name. Cochliasanthus caracalla and Vigna caracalla are synonyms, i.e. both are recognised names for the same plant, with Cochliasanthus the most recent. You may find plants labelled with either of these botanical names in nurseries. But confusingly there is also a very similar, dreadful, non-fragrant weedy plant which may also be called Snail Vine. It’s botanical name may be Vigna speciosa, although it sometimes labelled Phaseolus giganteus (not a botanically recognised name), and may even be labelled Vigna caracalla, in error. As all have similar foliage, it’s only when they flower that the difference can be easily discerned. In simple terms, the invasive Snail Vine has purple-only flowers, while the desirable, fragrant, non-invasive Cochliasanthus has a range of colours as the flowers develop, from white when in bud, to purple, followed by apricot yellow/orange as they age. As you can imagine, when the plant arrived from the nursery with a label of Vigna caracalla, rather than Cochliasanthus caracalla, I checked the plant and its name carefully, as the prospect of growing an invasive weed (spreading via underground runners) was a mistake I didn’t want to make. Interestingly both genera are pollinated by ants, something a bit more unusual in the plant world.
The result of planting this intriguing vine has been rewarding, with the drab, cold-affected foliage being refreshed at the start of spring, soon turning into a lush vine by December. A quick trim of the apical growth in December, breaking the apical dominance, results in abundant growth of flower-bearing laterals which continue through the warmer months into autumn.
PS the name Cochliasanthus means “ear-flower”. caracalla is said to be derived from the Portuguese caracol, meaning snail.
Andrew’s Plant of the week…….24.02.21: Scaevola albida ‘Pink Ribbon’
This week I thought I’d highlight not only a plant, but also the garden bed where it’s growing. The interesting difference with the Ellis Stones Garden, where Scaevola albida ‘Pink Ribbon’ is growing, is that the rocks have the priority and the plants are secondary to the design. The challenge in using plants then, is to ensure they don’t overtake or hide the granite rocks, as the rocks were intended to be the heroes of the bed Ellis Stones created. This bed, installed in 1962, is also exceptional in being the only area in the gardens that wasn’t designed by someone either commissioned or directly associated with the College, as it was then known. Ellis approached the Principal at the time, Tom Kneen, and asked if he could donate one of his Australian rock-outcrop installations to the Gardens. Ellis by then was very well known, so I’m sure his offer was quickly accepted. For those of you who don’t know much about Ellis Stones (1895-1975), he is a fascinating and highly significant Australian Landscape designer. http://anpsa.org.au/APOL25/mar02-1.html
His Australian bush garden designs, mostly characterised by the use of rocks, were a new, naturalistic style that ended up in all sorts of places; in fact the house over the road from me in suburbia has an Ellis Stones Garden. There are many inspiring aspects to his life, from overcoming being shot in the knee in the hail of bullets raining down on the row boats landing at Gallipoli in 1914, to a chance meeting in 1935 with Burnley Graduate Edna Walling on a country property where they were both working, Ellis as a carpenter-builder and Edna doing a garden design, which led to Ellis changing his career.
The pink flowering Fan Flower, Scaevola albida ‘Pink Ribbon’, nestled amongst Ellis’s rocks, has caught my attention over the last few week and reminded me of the second fiddle role it has to play. I’m always a bit hesitant to use pink flowers – I’m a bit ‘Goldilocks’ with them; the shade of pink has to be just right to entice me in. I tend to admire either end of its colour range, so I’ve surprised myself with liking this pale lolly pink flower colour. It seems to go so well with the textured and slightly sparkly granite rocks. Relatively new to the Ellis Stones garden, this Scaevola is growing well in full sun, in an irrigated bed. Usually we associate Scaevola with the purple cultivars, such as the well-known S. albida ‘Mauve Clusters’ or the larger-flowered S. aemula ‘Purple Fanfare’, which I love, but all Scaevola species and cultivars provide an excellent, long lasting display. Pink forms of Scaevola are less commonly seen, but are certainly available in the nursery industry.
Andrew’s Plant of the week…….17.02.21: Liriope muscari
One of the favourite places for many of us in the Gardens, especially on those really hot days that thankfully we haven’t had this year, is the Azalea Lawn. Along the shady edges as you enter from the east at this time of year is a beautiful display of dark purple flower spikes, from the well-known Liriope muscari, Lily Turf.
I mentioned Liriope muscari last week as one of the dependable, drought and shade tolerant edging landscape favourites, and the Azalea Lawn planting certainly explains its popularity. There are a few cultivars and species to choose from in the genus. The flower spikes of some are more prominent than others, in fact some are planted solely for their foliage effect, but for me, having flowers as well as great foliage seems too good to pass up.
Also in the Azalea Lawn, on the western top edge, is the white flowering cultivar, Liriope muscari ‘Alba’, sold and known as ‘Monroe White’. ‘Monroe White’ has slightly less prominent flowers than the purple form in the Azalea Lawn, but it is still worthwhile, as the white flower spikes look very striking against the dark green foliage. The Gardens also has a variegated liriope, and there are other even more variegated cultivars to choose from, if variegation is your preference.
The edging clumps of Liriope muscari in the Azalea Lawn have been there for well over 30 years, needing little attention, and were no doubt planted by Geoff Olive when a huge Monterey Cypress (Cupressus macrocarpa) was removed in the early 1980s, and the bed was redesigned after its removal.* Next time you walk over the wooden planks spanning the pathway into the Stream Garden (known as the Bog Garden in the 1980s-90s), you might like to recall that they came from the logwood of the removed cypress.
For a low maintenance, high visual impact, shade tolerant clumping plant, Liriope muscari is hard to beat. It is especially appealing when planted with burnt-orange coloured flowers. It’s a pity that Croscosmia x crocosmiiflora is such a dreadful weed, as the combination of its orange flowers with the liriope makes a wonderful display. For me, orange and purple is one of the very best colour combinations.
Andrew’s Plant of the week…….11.02.21: Tripladenia cunninghamii
A delightful smattering of mauve pink flowers greets you as you walk long the sawdust path in the Rainforest Garden during the summer months. Tripladenia cunninghamii is a wonderfully dense edging plant, and a perfect ground cover in terms of its height, density and method of spread (short, clumping rhizomes). Tripladenia seems to have a least three common names, Kreysigia (after its previous genus name, Kreysigia multiflora), Spice Bush (not very spicy if you ask me) and Bush Lily (a ubiquitous common name if ever I heard one). It is a monotypic (sole species of) genus of the Colchicaceae family, the same family as Colchicum, and also Burchardia that I highlighted last year. However, this family name seems to vary, with Convallariaceae and Uvulariaceae mentioned on older web sites.
Tripladenia’s native habitat is wet rainforests in northern New South Wales and Queensland, so its shade tolerance is no surprise, however it is surprising how drought tolerant (resistant?) it is, as the clumps always look good in the dry shade of the Rainforest at Burnley, and although the rainforest is drip irrigated, it certainly never seems to wilt. Snails and slugs (the thieves in the night!) tend to enjoy its foliage, but not enough to warrant doing any baiting or other method of control.
The pink, well displayed flowers are more abundant in the part shade/part sun sections of the Rainforest beds, beginning in late spring and continuing on into early autumn. It produces seeds, held in brown capsules, but doesn’t present any weed issues, as it hasn’t appeared elsewhere in the gardens since being planted more than 25 years ago. This was one of the plants that Phil Tulk (Garden Manager from 1987 to 2000), selected when he designed the Rainforest beds, using predominantly New South Wales rainforest plants that have interesting fruit and foliage. The Rainforest area is considered one of Phil’s finest legacies to the Gardens, and is a very clever way to marry up the dryer native garden on the southern side of the Gardens, with the greener English-style perennial border and English Oak on the north side of the rainforest beds, where the luxuriant native rainforest foliage blends the two together nicely.
Given the correct aspect, away from direct overhead sunlight, this dark green, attractive, dense herbaceous groundcover is a great choice for understory situations, and like a few other alternatives (such as Liriope or Clivia), needs little attention. Overall, a long- lived stalwart of shady places.
Note: don’t forget to click on the image for a full-size view.
Andrew’s Plant of the week…….03.02.21: Bupleurum handiense
This week I thought I’d highlight a relatively new plant to the Gardens, Bupleurum handiense, Jandia Anise. I found this plant in a Smith and Gordon plant catalogue a couple of years ago, and probably like you, any plant name I’m not familiar with entices me to look it up, to see what it is. Teena Crawford* (a Burnley Graduate), who was responsible for selecting the plant stock for the nursery (which alas closed down in 2019), always had either unusual plants or plants you couldn’t find elsewhere in her stock list. There was always a sense of excitement in looking through the catalogue each month to see what was new or newly available.
I’m unsure how Teena came across Bupleurum handiense, as it is limited in its range, and threatened in its native habitat. It occurs only on two eastern islands in the Canary Island group, so is not widely distributed in the world. As you will know, the Canary Islands contain numerous familiar, drought-tolerant plants; their sub-tropical climate and large variation in topography (from 1,400m mountains to the coastal fringe), mostly with only 250mm of annual rainfall (falling in November and December), makes them an ideal source of plants for Australian low rainfall landscapes.
One of the reasons I selected this shrub for the Gardens was for it’s glaucous blue foliage, with the bonus of greenish-yellow umbels of flowers during summer. It does set a large amount of seed, like most species in the Apiaceae family, that germinates freely below the shrub, so hand weeding is needed to contain its spread. Apart from that limitation, the low, compact shrub provides a lovely foliage display, that doesn’t require a great deal of pruning or input to retain its special qualities.
- A plant of the week that also highlights one of Burnley’s own. You can expect to see Teena appearing as a Burnley Graduate of the Month one month soon!
Andrew’s Plant of the week…….29.01.21: Araucaria bidwillii
At about this time of year, although not necessarily every year, a rather frightening occurrence takes place; the dropping of the large Bunya cones from the Araucaria bidwillii. Frightening, because the cones are so large and heavy; they’re at least the size of a football, and weigh around 10 kg. They are borne at the top of the canopy, and are well camouflaged, as they are dark green like the foliage; it’s difficult to see them when looking up into the tree, and to anticipate their shedding. Last Monday, at the height of the near 40-degree mid-day heat, the cones came tumbling down. Fortunately, as they are always at the very top, and the tree is pyramid-shaped, the cones tend to drop and roll through the branches below, and land not far from the tree itself. As the foliage is so dreadfully prickly, the chances of someone being hit is reduced, as people usually take a wide berth around the tree as they walk past on the lawn.
This particular Araucaria specimen, on the northern pond lawn, started a new tradition amongst the Burnley garden staff, of planting a tree on their last day of working in the Gardens. Martin Stevens, Burnley trained as an Associate Diploma arborist and Burnley garden staff member in the early 1990s, wanted to plant a tree in the Gardens to leave something to remember him by, and also as something for him to come back and appreciate. In 1995 when Martin planted the tree, Burnley had just a single Araucaria bidwillii, which is still standing at the east end of the herb garden. Considering how old this tree is (we believe it was planted somewhere between 1871 and 1890), it was decided to plant a new tree to eventually replace it. The site selected for planting the new Araucaria was on the east end of the north pond lawn, where a large Liquidambar styraciflua had recently been removed because of the failure of a bifurcated trunk.
Araucaria bidwillii has a remarkable history, and this article in the Gymnosperm Database is well worth reading. https://www.conifers.org/ar/Araucaria_ bidwillii.php It tells of its ancient past, it’s truly amazing hypogeal germination*, and its significant role and sacred status in the indigenous peoples’ ceremonies and tribal feasts. These took place every three years in the Bunya forests of south-east Queensland, and went on for as long as the seeds in the cones lasted. Individual indigenous custodians were responsible for climbing (yes, climbing the prickly tree!!!!) the tree and knocking off the large cones. Invitations on message sticks would then be sent out to attend the ceremonial feast.
Considering Araucaria bidwillii comes from rainforest regions in far north Queensland, as well as in the south east of the state, with over 1000mm of rainfall each year, it’s amazing the tree does so well in drier environments. They can become quite massive, up to 50 metres in their native habitat. The largest girth of a known specimen (measured in 2011 at Bowral in NSW) was a dbh of 215cm ( https://www.conifers.org/ar/Araucaria_ bidwillii.php)
*Hypogeal germination is unique in A. bidwillii, at least among conifers. It involves the seed first producing a root, then translocating its stored energy into an underground tuber, from which the shoot then later emerges. The leaf shoot can take up to two years to emerge from the tuber, and this was used to good advantage by the coastal indigenous people, who would bury seeds along the way back to the coast in damp areas, where they could later be dug up and the tuber harvested.
Andrew’s Plant of the week…….21.01.21: Xerochrysum bracteatum
Andrew says: “This week I thought I’d share a welcome surprise I recently had when walking along the central pathway of the Swan Street garden beds. There on the edge of the pathway was a self- sown, white flowering Xerochrysum bracteatum (Everlasting Daisy). While a white-flowering form is not unusual in cultivation, the fact that for the last five years the fact that all the other self-sown Xerochrysum seedlings throughout the Gardens have been yellow makes this one a standout.
As a cultivated plant, the Everlasting Daisy certainly lives up to its name, as they flower continually in warmer conditions, and are a wonderful inclusion for areas of the garden in full sun. There are several recognised selected forms and hybrids available, mostly yellow, but white and pink as well; some of these were chance self-sown natural hybrids, while others are a result of deliberate breeding, Annual forms seems to have a greater flower colour range; some of these were bred in America. There is also a slight variation in foliage colour, with some having more glaucous, blue-ish foliage while others are more light green in colour.
The perennial forms at Burnley are easy to establish, and their only drawback is that they tend to eventually open up from the middle as the stems split apart. Colder winters with damp conditions don’t suit their requirements either, so if you can muster the courage and plunge cuttings straight into where you want them to grow while they are still looking half reasonable with flowers, they will easily take root and begin flowering early next spring.”
Andrew’s Plant of the week…….15.01.21: Bursaria spinosa
I thought I would start the year with an Australian native plant, which although well known to horticulturalists, for the general public is a plant often asked about at this time of year, when it is in full flower. Bursaria spinosa, or Sweet Bursaria, is widespread throughout the eastern half of Australia, with two subspecies recognised, and a surprisingly large difference in height, from low-growing ground covers in the mountains to small trees on the coast.
Perhaps the general public tend not to recognise Bursaria spinosa because it’s one of those plants that “disappears” when not in flower, unlike its relatives in the Pittosporaceae, as it doesn’t have showy, colourful fruiting capsules or seeds, instead having clusters of small, dry, brown capsules that are shaped like old-fashioned purses, and rattle in the wind when the seed inside is ripe. These fruit give the plant its name, which is derived from the Latin bursa, meaning a purse.
Probably the most important aspect of this species, and what creates a sense of wonder and delight, is the symbiotic relationship it has with a species of ant and a species of butterfly, and not just any butterfly, but the rare and endangered Eltham Copper Butterfly Paralucia pyrodiscus lucida.* There’s a great yarn to be read here: https://www.recreatingthecountry.com.au/bursaria-spinosa-sweet-bursaria.html, that provides greater detail of the wonder of this butterfly life cycle. Essentially, the larvae of the butterfly live underground below the Sweet Bursaria shrubs, in ant nests, and from late September until they pupate in early summer, every night, a team of four guardian ants guide the individual caterpillars out from underneath the plant to feed on the bursaria leaves. Then early next morning, the ants guide them back to their nest underground, where the ants feed on the honey secretion from the caterpillar’s abdomen. Once it emerges from the pupating stage, the butterfly feeds on the nectar of the Bursaria flowers, and then the female lays its eggs on the roots of the plant, where the tiny ants then dutifully guard them until they hatch.
Bursaria spinosa, as its name suggests, has spines along the branches, some plants more so than others, but especially the young shrubs, which are very prickly. These are not too off-putting as a garden shrub though, and the species is adaptable to a wide range of tolerances and uses. It will grow in full sun to shade, and can be grown as a tall single trunked small tree, or coppiced to the base for a multi-stemmed specimen. Bursaria spinosa will reward you each late December and January with panicles of sweetly fragrant white flowers that even on the hottest of days, still look fresh and appealing. Its drought tolerance is outstanding, and while it self-seeds freely, the seedlings are easily spotted and removed if unwanted, and tend to be individuals rather than germinating in large groups.
So for those living in the surrounding suburbs of Eltham, growing bursaria is a must, and for the rest, planting bursaria in your garden has great reward with little effort.
* Although named the Eltham Copper, the species is found in ten sites in the Eltham-Greensborough area, three separate small populations in the Kiata-Salisbury area in the Wimmera, and three sites in the Bendigo region in rural Victoria. There are also small populations at two sites at Castlemaine.
P.S. Note from Jill. It’s great to plant Bursaria spinosa: it attracts all sort of insects when in flower, and other butterflies than just the Eltham Copper. But you won’t have Eltham Coppers unless you have the right kind of ant (Notoncus sp).
Andrew’s Plant of the YEAR…….22.12.20: Alyogyne huegelii x hakeifolia ‘Natalie Anne’
And the winner is…. Alyogyne huegelii x hakeifolia ‘Natalie Anne’
Not only does this plant have the longest name of all the POTW I have done this year, but it also has been flowering the longest. Despite the fact I highlighted this POTW on the 19th July, it had already been flowering from at least early May, in fact, does it ever stop flowering?
While there are other long flowering plants at Burnley, one in particular which I didn’t highlight this year is Cuphea ignea ‘Starfire’ (thanks to Geoff Olive for bringing this to the Gardens), sooner or later the Cuphea needs a severe cut back to stop the branches opening up and so losing its shape. The Alyogyne on the other hand can tolerate the occasional light prune which doesn’t impact its continual flowering habit, so it’s not what I consider a ‘feast and famine’ type of plant.
I’m glad I was able to provide a flowering snap shot throughout the year for those of you who couldn’t come in to Burnley and see it for yourselves. I started ‘Plant of the Week’ at the beginning of May, and now 34 weeks later I can tell you the Gardens have been thriving, and have been appreciated (I’m tempted to say by an unprecedented number!) by what seems like thousands of people throughout 2020. Many people, despite living locally, had never visited the Gardens before, while others that were regulars, relied on them to provide distraction and solace for troubled times.
Runner up Plant of the Year goes to Auranticarpa rhombifolia, which still has a moderate display of orange berries, with an equal number of white flowers promising an assured continuance for another outstanding year ahead.
Most improved plant goes to Erythrina x bidwillii, which, when last highlighted in August, was masquerading as a non-living pile of something, and look at it now: the bright red flowers will continue until Autumn.
Wishing you all the very best for the year ahead and I hope the Christmas-New Year festive season gives you the opportunity to re-connect with those you have been itching to catch up with.
Warm regards, Andrew
Andrew’s Plant of the week…….06.12.20: Dierama pulcherrimum
This week I’m highlighting a delightful long- lived evergreen perennial, Dierama pulcherrimum, with an equally delightful common name of Fairies Fishing Rod or Angel’s Fishing Rod, or wandflowers, or graskiokkies, depending on where you live in the world.
The Southern African genus Dierama, a member of the Iris family, with 44 species, is rather aptly named after the Greek word ‘funnel’, reflecting the distinctive funnel shape of the flowers. The highest concentration of Dierama species is 26, found in the south east corner of the Cape, in the Kwazulu-Natal province, with the remaining species having a varied range from the highlands in Ethiopia to the Southern Cape.
Dierama species have contractile corms, meaning that they form a new corm under last year’s corm, so can end up being quite deep-seated in the ground. Perhaps this is why they take some time to re-establish if dug up or divided, so are best left undisturbed if you want reliable flowering.
Like some bulbs that you find growing in the middle of no-where, sometimes you find Dierama growing where once a farm house or old garden once stood, and all that remains of the garden today is a giant Bunya Bunya (Araucaria bidwillii) or a grassy-foliage clump that has the dancing, slender stems of the Fairies Fishing Rods, seemingly, when viewed from a distance, floating in mid- air.
Dierama pulcherrimum has two main flower colours. Light pink is the more common colour, but recently the darker pink form has become popular, and it is the one I chose when re-planting the Sunken Garden in 2018. It was one of the few plants chosen that wasn’t perfumed or fragrant in some way, but the prospect of planting it in the narrow bed, where it can gracefully play in the wind as you walk down the ramp, was too tempting to forego. It was also a plant Geoff Olive loved and as Geoff was the original designer of the Sunken Garden, I thought it an appropriate choice.
The lighter pink flowering clumps in the Perennial Border have been there ever since the original planting in 1985, with the only maintenance needed being an occasional removal of the dead foliage and annual removal of the slender flowering ‘rods’ once the clumps have finished flowering at the end of summer.
Andrew’s Plant of the week…….08.12.20: Strophanthus speciosus
This week I thought I’d mention another poisonous plant from the Apocynaceae family, Strophanthus speciosus, with a common name that makes its habit and qualities obvious: Poisonous Rope.
Some may consider the flower beautiful but for me there is something a bit sinister in how it looks, with its spidery, orange and yellow long sepals not something one wants to fully trust.
In southern Africa (Zimbabwe and Mozambique), where it comes from, growing on the edges of forests, the seeds were used as an arrow poison and the fruit as a spear poison. Nasty stuff. However, it does have medicinal qualities, with a glycoside extract used as a cardiac stimulant, and the roasted roots used to make a powder to treat snakebites. I’m not sure what would be worse, the snakebite or the cure, you certainly would want to trust your local medicine–man.
The specimen at Burnley has been growing at the base of a large tree for a long time, never needing much attention apart from curtailing its climbing habit up into the tree. It’s certainly eye catching when
in flower, and the seed pods when they split open form a two-horn-shaped capsule that contains fluffy, wind dispersed seeds. Like last week’s plant, they don’t self-sow in the Gardens so it isn’t considered a weed problem.
Andrew’s Plant of the week…….01.12.20: Oxypetalum caeruleum
This week, the first week of Summer, I thought I’d highlight a plant that will continue flowering all the way through to autumn, with a lovely common name of Tweedia: Oxypetalum coeruleum (syn. Tweedia caerulea). Tweedia is named after James Tweedie, a gardener in the 19th century who worked at the Edinburgh Royal Botanic Gardens, in Scotland.
This small, rather straggly plant is best planted in tight groups, however its density can be improved by pinching out the top of the growth apex in late spring, to encourage lower side branching. Being part of the Apocynaceae family, it has a milky, latex sap when cut, which is poisonous if ingested, and I wouldn’t want it anywhere near my eye or skin either. The common name of this Family is Dogbane, because some of the genera in the family were used as a dog poison. The sap has also been used as an arrow poison.
Like numerous other blue flowering plants, Oxypetalum coeruleum comes from South America, in Brazil and Uruguay, and is better known as a twining sub- shrub, although what we have growing in the blue border doesn’t have a twining habit. I got this plant from Geoff Olive’s garden, where the turquoise-blue flowers really took my eye.
There are so many shades of blue for flowers and in this case the blue is more sky blue in colour, not as common as most blue flowers, so a lovely addition to the front of a bed where your eye is immediately drawn to its luminescence. It lasts well as a cut flower and the boat shaped seed pods and attractive grey- green, arrow-shaped foliage also adds some ornamental appeal. While I thought the fluffy, wind borne seeds, rather like that horrendous, insidious weed Moth Vine (Araujia sericifera, in the same family) that remains hidden and un-noticed amongst other foliage, the seeds of the Tweedia don’t seem to self-sow and haven’t been a weed issue in the Burnley Gardens.
Andrew’s Plants of the week…….25.11.20: Streptosolen jamesonii ‘Ginger Meggs’
This week I bring you a big ray of sunshine from the dwarf cultivar of Streptosolen jamesonii, with the rather lovely Australian name of ‘Ginger Meggs’. For those who don’t know, Ginger Meggs was Australia’s longest running comic strip (created in the 1920s) and featured a red-haired, pre-teen larrikin from a suburban working-class background. He was forever getting into strife, something this plant namesake has no trouble with.
I’m sure most of you would have spotted the taller form of this brightly coloured South American shrub in your travels; usually it’s a rather straggly, open shrub that requires severe pruning each year to maintain some order. The dwarf cultivar is therefore a great boon, as it has all the fine attributes of the long flowering species, in a more compact form. A few light clips is all this shrub needs each year to keep its desired shape, and its only drawback is its lack of cold tolerance, which can affect the late spring flower display.
I must say, I’m rather fond of the warm colours this shrub brings to the garden, with the colour variation of the aging individual flowers providing great visual interest, and for me, never failing to bring joy to a sunny spot in a garden bed.
Andrew’s Plants of the week…….17.11.20 Rhododendron ‘Fragrantissimum’ and Crataegus tanacetifolia
This week I thought I’d highlight two plants, as they seem the antithesis of each other, apart from the fact that they flower at the same time of year. You become aware of this contrast as you walk past them and detect the aroma in the air, one rather nice and the other quite the opposite. In the case of the aptly named Rhododendron ‘Fragrantissimum’, the fragrance has a lovely lemon-citrus aroma that you tend never to tire of (unlike the rather cloying fragrance of some jasmines, for example), that matches its ‘Lady Di’ qualities, with its white, beautiful, demur appearance.
The flowering of Crataegus tanacetifolia on the other hand is a bit confronting. One couldn’t call it a fragrance as such, more like something half rotten; a 3-day-worn- socks sort of smell. As a strategy for pollinators, this seems very versatile and rewarding, as there is an incredible variety of insects that are attracted to it, including large flies, who are perhaps tricked into thinking it is something to lay their eggs on, although they do eat the flower nectar when visiting as well. Other pollinators include bees, beetles, hover flies and butterflies; come one, come all, we have something for everyone. The end result of all this pollination work is an abundant crop of large, brightly coloured, edible berries (they’re pomes really, for the purists), that last well throughout the late summer and autumn period.The pollinators of R. ‘Fragrantissimum on the other hand are less easily seen, perhaps bees, but the plant doesn’t end up setting seed and being a cultivar, you probably wouldn’t want seed variation anyway.
As for their tolerances and where they grow best in the Gardens, this couldn’t be more different either. The crataegus comes from western Asia, where it grows on exposed rocky slopes, so very drought tolerant, although also incredibly tolerant of periodic saturated soils as well. The opposite can be said for R. ‘Fragrantissimum’, as its preference is for irrigated, semi-shaded positions, certainly not exposed to the hot westerly sun, and shelter from the wind will protect the beautiful, large white flowers from being stripped off, as happened last night (15 November) in the horrible, hot, northerly gale. It was looking so good last week, although it did wilt in the noon-day heat, but today there is hardly an intact flower left. Thankfully there are plenty of buds still to open, so all is not lost. The crataegus was barely affected by the strong wind, as shown by the insect activity this morning, something I’m sure they were thankful for.
Andrew’s Parastic Wasp ? of the week …….11.11.20 Aphidius rosea
Warning, if you have experienced fear and loathing from watching the Sci-fi Alien films, reading further may produce un-easy flashbacks. Or, if you are feeling queasy in the stomach right now, best read this when you are feeling more settled.
A slight deviation this week to highlight one of the most successful biological control releases for a plant pest in Australia, the tiny wasp, Aphidius rosea.
To give you some context on how transformative this wasp has been to rose gardens throughout the southern part of Australia, you only have to go back to pre-1993, when horticulturalists had the trepidatious regular chore of spraying insecticide to control rose aphids. The insecticide of choice at the time was Dimethoate (Trade name Rogor), a contact and systemic insecticide that really stank; even though you wore a respirator, the smell still went through the cartridges.
So, you can imagine our relief and excitement when Burnley was chosen as one of the release sites for a wasp that would end all our pesticide spraying. In fact, it was imperative for the wasp’s survival that no insect spray of any type be used; we were just to leave it up to the wasp to control the pest. Sounded alright to me.
The really good thing about this biological control was the fact that the wasp life-cycle could survive over the winter period, even in colder areas like Castlemaine, which enabled the wasp to be released just once for on-going aphid control forever!. Brilliant!
There is a slight downside to this process, due to the delay in getting the aphid initially under control each season, as the wasp has to play catch up with the spring aphid population explosion. That’s why, if you go down into the rose garden now, you will see aphids everywhere and it looks as if you need to intervene, however we stick to the plan and wait for the bell curve of control to take its natural process.
The parasitic wasps are very small and difficult to see: about 3 mm in length, with long antennae. The female wasp flies about, and inserts a single egg into an adult or nymph (juvenile) aphid; one wasp can lay a large number of eggs in a short period of time. Each egg insertion into the body of the aphid takes less than one second.
This is where the rather squeamish part happens (the scary sci-fi film Alien comes to mind). The egg hatches inside the aphid and proceeds to eat it from the inside out, rather like being trapped inside an edible gingerbread house and having to eat your way out! The first sign of an infected aphid is when they turn a nasty bronze colour; they wander off on their own, complaining of a belly ache, and soon turn into a brown, bloated mummy. Once fully developed, the wasp then chews a hole through the external husk of the aphid (which is all that is left), and proceeds to join its brethren in the summer feast. You may just be able to see in my photo a hole in the side of one of the aphid mummies where an adult wasp has emerged.
Interestingly, in the spring of 1993, when the infected aphids were released in numerous places throughout Victoria and South Australia, some sites were more successful than others in establishing an ongoing colony of wasps. The research paper attached here https://digital.library.adelaide.edu.au/dspace/bitstream/2440/18781/2/02whole.pdf describes the outcome and success of releasing sufficient numbers into a rose site (a minimum of 40 roses) to ensure ongoing establishment, and the wasp’s ability to migrate to other areas nearby. In the case of Bendigo, where the infected aphids weren’t released, they appeared the following autumn having travelled 35km from Castlemaine where they were released the previous spring.
While we have other biological controls for pests, such as the predatory green-house thrips, which don’t survive more than a single season, the parasitic wasp is well adapted to the life cycle of the aphid and hibernates each winter to await spring. For the predatory thrips it’s a rather bleak life, as they need to be constantly re-introduced either when the night time minimum temperature is above 16 degrees or when the predatory thrips run out of prey and then turn cannibal, a rather grisly affair where the final all-conquering predatory thrip is left alone to ponder their demise.
It’s a strange world out there in insect land.
Andrew’s Plant of the week…….04.11.20 Aristea capitata
The flash of intense violet blue that catches your eye as you walk down the pathway into the Gardens this month is the striking Aristea capitata. This South African evergreen, tucked away at the back of the Kirkhope rockery, remains un-noticed until Spring, when the tall, upright flower stalks start to bloom. The flowers are best seen in the morning, when the individual flowers, which only last a single day, are open. The display goes on for more than a month, with a succession of new flowers developing in clusters up the sturdy stalks. Visited by bees, the plant has worked out a pollinator strategy to keep them coming every day, give them a little and they’ll come back for more. Unlike the other weedy Aristea species that we have in the Gardens, Aristea ecklonii, Aristea capitata doesn’t self-seed at Burnley, instead, having to rely on an underground rhizome to ensure its long-term survival.
Although we tend to think that most South African plants are drought tolerant (with the largest number of succulents species in the world), Aristea capitata prefers the gentler, more fertile soil on the lower slopes of the mountain range, in the Cape region in South Africa. One of the places in which it’s commonly found is the much-visited Lions Head mountain (670 m) in Cape Town. This well-known landmark has an interesting geology, a bit like a layered cake, with three rock types: sandstone on top, volcanic basalt in the middle, and clay shale at the bottom. It is in the bottom shale layer where this Aristea species can be found, in depressions in the ground where it can take advantage of the winter and spring rainfall that predominates the in southern Cape region (its common name is Marsh Aristea). The species is just one of an amazing 7,000 plant species that make up a biome* known as the Fynbos (‘fine-leaved plants’), which occurs in a 100-200-Kilometre-wide coastal strip on the west and east side of the Cape in South Africa.
With about 70% of these species being endemic (only found in that region), its biodiversity in a such relatively small area is one of the reasons this biome has been declared one of the 6 Floral Kingdoms in the world. By comparison, plant diversity in the Grampians Gariwerd in Victoria, which we consider to be high at 1.7 species per km2 (975 species in an area of 1,670Km2), is dwarfed in comparison to the Fynbos, which has 12.85 species per Km2. No wonder it has been given its status as a Floral Kingdom. Although one of the smallest of the six, at 90,000 Km2, it is the only Floral Kingdom contained in a single country. The plants that survive here have adaptations for fire, and for the majority, for poor, infertile soils. The rhizome of Aristea capitata has the ability to re-generation after fire, but the species is not tolerant of the infertile soils that the majority of Fynbos vegetation is adapted to.
*a large community of flora and fauna occupying a major habitat, such as forest or tundra.
Andrew’s Plant of the week…….19.10.20 Rosa odorata ‘Mutabilis’
With peak rose season in full display, not just at Burnley but all throughout the southern states, I thought I’d focus on one of the more unusual and significant roses, in terms of European plant breeding, that Burnley’s Rose Garden has to offer.
This area of the Gardens, previously a lawn, has been the designated area for roses since the perennial border displaced them in the early 1980s. This was one of the first, if not the first, garden bed designs where its primary function was as a teaching and learning display for students. The garden was laid out to show the development of the rose through history, rather than a collection of roses for ornamental display. This was of course the genius design work of Geoff Olive, the prominent Burnley lecturer and designer I’ve mentioned earlier this season (Wisteria sinensis).
Rosa odorata ‘Mutabilis’, (or Rosa x odorata ‘Mutabilis’, or R. chinensis ‘Mutabilis‘, but that’s another story) is rather fascinating and unusual, as the petals change colour quite dramatically as they age. They start out pale yellow/apricot in bud, open to a light pink, then as they age further, continue to darken until they are a dark pinkish red. The plant itself is virtually thornless and not a rose that you would prune heavily, as it tends not to re-generate well from older wood, unlike modern roses.
This cultivar was chosen by Geoff to illustrates the traits of Chinese roses which transformed rose breeding in Europe two hundred years ago. The most exciting new trait was having a rose that flowered continuously (until the winter cold sets in), rather than just few a few short weeks in Spring. Imagine the excitement in the 1800s when perpetual flowering became available for rose breeders. Other new traits included a true, longer-lasting red petal colour and a previously unavailable dwarf habit. There was also the addition of new fragrances to be had, the common name China Tea Roses reflecting the tea fragrance of the flower, plus a fruitier fragrance not previously present in European roses. Still, the fragrance of European roses by far surpassed anything the Chinese roses could
produce. There had been rose breeding in China for up to 1000 years before Europeans got hold of the four new cultivars between 1792 and 1824 (The Stud Roses) but it was only in the early 20th century that C.C. Hirst (1870-1947) did pioneering genetic research work to identify and detail the chromosomal rose inheritance story. It seems the dark lasting red and dwarfism traits are on the same chromosome.
What ever the back story, this Rose is a delight when in flower and like only a few of the genus, isn’t badly affected by black spot fungal problems, always a bonus when it comes to roses.
Andrew’s Plant of the week…….19.10.20 Wachendorfia thyrsiflora
One of the first perennials to begin flowering each year in the Perennial Border is the rather striking tall Wachendorfia thyrsiflora, which has the very appropriate common name of Bloodroot, due to the amazing red colour of the fleshy rhizomes.
Endemic to southern Africa, where its natural habitat is on the edges of streams and permanently saturated soils in marshes, very similar to Phormium tenax, which grows in water-logged New Zealand habitats, it success in our border shows how adaptable this plant is to drier conditions, if given irrigation. The Family, Haemodoraceae, is the same as the Australian Kangaroo Paw, Anigozanthos, which will also tolerate periodically waterlogged soils.
The Wachendorfia genus (don’t you just love that name), has just 4 species, with W. thyrsiflora the only evergreen one, the rest being summer dormant. The elegantly textured, pleated leaf blade, is reason enough to plant this tall perennial, let alone the multiple 2.5 metre stalks of golden yellow flowers that emerge in late September and continue through until early summer.
Planted in the Perennial Border, then known as the Herbaceous Border, in the early 1990s by Phil Tulk (Gardens Manager 1987-2001) it has been surprisingly low maintenance, as we have never dug up and disturbed it, just cut off the finished flowering stalks each year and left it alone.
PlantSAfrica.com, the website of South African National Biodiversity Institute, gives a good run down of this species, and mentions, among other things, the curious pollination puzzle; the nectar is abundant and accessible but the pollen and stigma are undisturbed when the nectar is taken. So, the pollinator of this genus is unclear. Add to this, that in some populations the stigmas lean to the left, while in others it leans to the right, and that one of the stamens is bent in the opposite direction to the stigma, and you end up leaving it up to the botanists to sort out. A paper in the American Journal of Botany http://labs.eeb.utoronto.ca/barrett/pdf/schb_185.pdf goes into detail on the left and right sided style position of the flower (officially known as enantiostyly) . It seems Wachendorfia is unusual.
Andrew’s Plant of the week…….14.10.20 – Burchardia umbellata and Linum marginale
Another chapter in Burnley’s history. Andrew tells us: “If you are fortunate enough to live nearby a native grassland reserve, from what I’m hearing from others, this year is providing an outstanding display. While Burnley’s flowering grassland display in no way compares with what you find in some bushland settings, there is a story of perseverance worth telling, both in terms of research and endeavour, that has brought this garden area to where it is today.
30 years. That’s how long we have been developing this flowering grassland area in the Native Garden. It’s been a long saga, rather humbling in a way, as, in 1991 when we first started to introduce native forbs (flowering herbaceous plants) into the gaps between the grass clumps, we thought it would be easy, just like doing a perennial border. How wrong we were. Perhaps if the beds were irrigated it would have been easier to keep the tube stock alive. However, that would only have exacerbated the exotic grass weed problem, the main stumbling block to this area’s success. And besides, a major part of James Hitchmough’s original plan for the grassland was for it to be un-irrigated, an example of what urban parkland could look like, to be more than just the usual mown grass.
In 2011, a breakthrough happened when several Burnley staff members got together and decided to implement the same techniques used in larger scale projects that researchers at Burnley were having success with, such as the scalping of weed-laden topsoil from sites prior to seeding with the forbs and grasses that Paul Gibson-Roy was doing so successfully. Sue Murphy, Melanie Conomikes,and John Delpratt got together and planned what was needed. After some initial misgivings from an arboriculture staff member about tree root disturbance from removing the soil below an existing tree, the renovation of the first area was completed. This was closely followed two years later with the bed opposite, and once it was clear, we were onto a winner.
However, one of the past constant disappointments once more reared its ugly head: how to get the planted flowering forbs to survive a single summer and establish themselves for an ongoing spring display. Many of our flowering lovelies just wouldn’t comply. For one of those flowering delights, Burchardia umbellata (Milk Maids) – and this is where the perseverance fits in – John Delpratt decided that some patience and nursery coddling was needed. Quite a few of the native forbs have edible tubers, like the Yam Daisy, and Milk Maids also has a tuber harvested as an indigenous food source. By nurturing the germinated seedlings of Milk Maids over a two-year period in the nursery, the tubers developed sufficiently for them to be planted out into the semi-hostile environment of the grassland, to subsist and overcome the summer desiccation challenge. A small group of Milk Maids are now flowering successfully, more than a year from when they were planted out. One summer down, hopefully many more to come.
Another success in the grassland bed is Linum marginale, Native Flax. While it doesn’t have a tuber to subsist on, its self-sowing capability seems to have been a successful strategy in ensuring its survival, for what has now become more than one season. Mind you, its nowhere near where we originally planted it, as it has found its own niche more suitable to its environmental tastes, right on the edge of the pathway, and also among the rocks on the lower end of the bed. John and I noticed a wall-to-wall seed germination on the edge of the path 12 months ago, and from bitter past experience, we didn’t expect them to survive a summer onslaught from heat and slugs. Wrong again it seems. This spring, the multitude of plants are flowering profusely and as you perhaps can detect in the photo, show up as being a big part of this year’s display.”
Andrew’s Plant of the week…….06.10.20 – Rhodosphaera rhodanthema
Andrew tells us another interesting story, with a bit of Burnley’s history, and some of the research that happens at Burnley to make our cities better places. Andrew says: “A splash of red meets you as you walk down the path towards the Burnley Rainforest this month.
The red splash comes from an Australian rainforest tree, Rhodosphaera rhodanthema, Deep Yellow Wood, that is more widely grown in Queensland, where it’s used as a street tree, than in Victoria. From a distance, you’re not sure what the red expanse of colour is, but upon closer inspection, it turns out to be the flowers, except that the red colour is from the flower buds that haven’t opened yet; when they do open, the pink petals and yellow stamens make the colour blend look like something in a lolly jar.
It’s always intriguing when a plant has only a single species for the entire genus (monospecific), which is the case with this genus; it makes you wonder why other species didn’t develop.
This medium sized tree (up to 25 m, but less in cultivation) grows from northern New South Wales up to Maryborough in south-east Queensland, and like a few select plants in the Gardens, was donated after a student had finished their work studying it. The student in this instance was Geoff Williams, one of the two younger brothers of current honorary Chris Williams (all three brothers studied at Burnley). Geoff was one of lecturer James Hitchmough’s Hort Project students in the fourth year of the old B. Hort; he later converted to a Masters in Urban Horticulture under Burnley Principal Greg Moore after Hitchmough left in 1992.
James and Greg were interested in finding out more about tree provenance, and its potential role in selecting more suitable trees for urban environments such as streets, particularly with regard to greater compaction tolerance. James’ hypothesis was that this or other perhaps under-utilised tree species, whose origin was in periodically flooded soils such as dry rainforest, would be more suited to the typical compacted soils found in today’s cities. Geoff Williams began his investigations on the dry-rainforest species grown by nurseries and forestry departments, and once the ground work had been established, he went on a road trip, collecting seed of trees from various dry-rainforest areas (provenances) of New South Wales and southern Queensland. The seed he collected from the trip was then grown on in Burnley’s nursery, and the young trees were put through a series of trials by flooding/water logging, to test the compaction tolerance of the various provenances. It is interesting that water-logged soils have the same effect on plant growth as compacted soils: it’s all about a lack of air space, which is essential for plant growth (unless it’s a mangrove with aerial roots).
The Burnley Rainforest beds, newly designed and planted up in 1992, suffered a calamity within a few months of planting, when a severe frost wiped out the planted tube stock. Although Geoff’s Rhodosphaera was not included in the original design, the prospect of planting one of his crème-de-la crème trees was too tempting to pass up, and space was made available on the western end of the bed when the Rainforest Garden was re-planted. It certainly hasn’t disappointed, providing a most unusual display each October.”
Jill says: you might be interested to know that this Australian dry rainforest tree is in the same plant family as the familiar Peppercorn tree, which originated in South America. The family is the Anacardiaceae, or Cashew Family
Andrew’s Plant of the week…….29.09.20 – Acacia redolens and Acacia daviesii
Andrew says: I realise I’ve been rather remiss in not featuring any Wattles this month, so to make amends, this week I’ll feature two: Acacia redolens and Acacia daviesii.
Acacia redolens, the Vanilla Wattle, is a ground cover extensively used in drier regions on the west coast of America, where it’s grown in median strips, along freeways and in car parks. In Australia though, it’s less commonly seen or used. Like many Australian plants grown in other countries, this wattle is considered a weed on the west coast of America. The plants we have at Burnley have been there for many decades, discrediting the Arizona State University assertion that it is short lived. John Rayner (long standing Burnley staff member) remembers this patch of A. redolens in the native garden as a student in the late 1970s, so it was planted before Kath Deery remodelled the area in 1987. This wattle is endemic to the south west region of Western Australia, with several natural forms being evident, from 3-5 metre trees to low mounding ground covers, like the plants we have at Burnley. Its natural habitat is saline and alkaline soils, such as on the margins of salt lakes. Phil Tulk, the Gardens Manager from 1985-2000, showed us a rather neat trick when we were under his tutelage as gardeners. If you rub the leaves (phyllodes) together with water, it foams up and creates a fragrant soapy substance good for cleaning your hands.
The other Acacia, A daviesii, was donated to the Gardens by Cathy Olive, Geoff’s daughter (I featured Geoff last week with the Wisteria sinensis POTW). This acacia is very curious, as it hasn’t been known to set seed, and has a very limited distribution around Mount Timbertop in central Victoria. Cathy thought that planting a specimen from a cutting at Burnley may increase the possibility of it setting seed. This acacia is considered vulnerable in Australia https://vicflora.rbg.vic.gov.au/flora/taxon/3b2a87ee-27d5-40cf-9f83-b74814b0290f , and while VICFLORA describes it as a suckering shrub to 2.5 metres high, Cath has given me some additional information that indicates some variation. Cath has visited the Mt Timbertop area on several occasions, and observed nine small patches, growing as three distinctive different populations. One population growing in a gully hasn’t been disturbed like the other two (by fire in 2006 or bulldozers doing fire break works), and is much taller, growing to 2 metres in height. The other two disturbed populations are only knee high and have suckered extensively, whereas the taller, undisturbed gully population are straggly, single stemmed specimens with no suckering evident. Certainly, there is no sign of the specimen at Burnley, planted in 2016, suckering yet, and I suspect unless I cut it down or disturb the soil around it, there is little likelihood that it will.
Andrew’s Plant of the week…….22.09.20 – Wisteria sinensis
Andrew says: “This week I couldn’t ignore highlighting the Wisteria sinensis, the Chinese Wisteria, that has just started to flower.
We have four areas in the Gardens where this wisteria species grows: two are trained onto pergolas, and the other two are maintained as large shrubs. The flowering of the wisteria each year is of special significance to Burnley, as it occurs at the same time as the anniversary of Geoff Olive’s passing (in September 2016). Geoff Olive, for those who are not familiar with his name, was a long-standing Burnley staff member, who encompassed several roles (managing the nursery, managing the gardens, and teaching), and is considered one of the two most influential designers of Burnley Gardens (the other being Charles Bogue Luffmann). While Luffmann is considered to have redesigned the Gardens (in the1890s), and to have introduced greater shrub mass to garden beds, Olive is responsible for designing and in some cases selecting the plants for multiple areas (the Rose Garden, the Herb Garden and the Sunken Garden) and what he didn’t design, he added to and improved with great skill. Olive was a great admirer of wisteria, and planted the two specimens on the pergolas opposite reception and at the top of the Azalea Lawn that are such a drawcard at this time of year for visitors to the Gardens.
Unlike the Wisteria floribunda growing along the Wisteria Walk, W. sinensis has a wonderful perfume, and if you can keep the possums away, provides a stunning display in Spring, with a lower-key, second flowering in mid-summer. Careful training and patience is needed to ensure the best flowering display, as wisterias flower on two year old stems, so the initial pruning when first establishing the vine is to prune and re-prune stems to develop flowers as close as possible to the main stems .
Wisterias are strong, woody vines that easily self-layer into adjoining garden beds, if stray tendrils are left undetected, and any structure they grow on had better be sturdy, as their stems turn into boa constrictors that crush and outlast most wooden structures. Extemely long lived, drought tolerant and, apart from possum grazing, pest free, this climber, once formatively pruned, provides good shade and a spectacular floral display.
P.S. special thanks to the Friends of Burnley Gardens who funded the replacement of the Wisteria Pergola opposite reception in the early 2000s.”
Andrew’s Plant of the week…….15.09.20 – Salix fragilis
The things gardeners have to do! Andrew says “This week, I thought I’d focus on one of Burnley’s iconic trees, Salix fragilis, the Crack Willow that grows on the edge of the Luffmann Lily Ponds. A 25-metre tree if not pollarded like Burnley’s specimen, it gets its common name from the sound the branches make when broken. They tend to be a bit scruffy and prone to decay and insect attack as they mature, and they are also an environmental weed in many states in Australia, which we can attest to, as one year we chipped the branch prunings onto a concrete slab, only to see each little bit start to send out leaves, a frightening sight. Burnley’s tree is a strange, rather decrepit specimen; new- comers to the Gardens might perhaps wonder why it’s still there.
It’s certainly a survivor, you can’t get much more resilient than this. Its planting date is uncertain, but was probably sometime in the mid to late 1890s, when the Lily Ponds were believed to have been installed by Luffmann during his tenure as Burnley’ first Principal. Folklore has it that the students dug out the ponds by hand, and the site was chosen because it was a boggy depression in the lawn. The earliest archive photo of the tree we have shows it well established in 1915.
When Paula Cave and I cleaned out the ponds in 1990, in preparation for Burnley’s 1991 centenary, Phil Tulk, the Gardens Manager at the time, recognising the tree’s importance and the seemingly precarious state it was in, duly took a stout stem from the tree and plunged it straight into a spot on the other side of the pond. His feeling was that the original tree wouldn’t last, and a clone was needed to replace it. The plunged stem grew and is now well established, but the decaying original tree 30 years later is alive and well, albeit somewhat worse for wear.
This was probably one of the earliest instances in the Gardens’ history of recognition of a tree that needed to be propagated to ensure its longevity due to its historic status. In an earlier example (in the 1960s) a clone was taken from another one of Burnley’s iconic trees, a Californian Redwood (Sequoia sempervirens). This was planted in the South Island bed, but it is not known if this was done to preserve the tree, or just to add a feature tree to the end of the bed.
The significance of Phil Tulk’s unusual action in replicating the Salix fragilis is increased when you consider how few of Burnley’s trees have been cloned or propagated to replace the original tree. As a rough guide, Burnley has over 600 trees, of which around 260 are individual species; of these about a dozen have been cloned. Space is tight for trees in the historic section of the Gardens, as a tree, you need to be very special to be replicated, especially while you are still alive, like the Salix fragilis by the ponds.
Andrew’s Plant of the week…….07.09.20 – Prunus glandulosa
Andrew says: For most of us, there is a flowering genus that we fondly associate with springtime, whether it be Wattle (Acacia species), Prunus, Daffodils (Narcissus species), or perhaps one of our Australian wildflowers such as Chocolate Lilies (Arthopodium strictum).
Prunus (Latin for Plum tree) is well known to all of us, with ornamental flowering shrubs and trees, and fruiting cultivars of plums, almonds, peaches, cherries and apricots grown in gardens and orchards all over the temperate world. They can be evergreen or deciduous, range from 30 metre tall trees to 1.5 metre shrubs, and flower in most, if not all seasons. In some regions of the world they are a symbol of endurance and hope, and in Japan cherry blossoms are celebrated for the coming of new life. Depending on how the genus is defined, the number of species could be from 150 – 400 or more (https://vicflora.rbg.vic.gov.au/flora/taxon/7238d77c-bfd9-451e-abdc-2e687ca3074b). Australia even has two species, e.g. P. turneriana, to 30 m, growing in North Queensland rainforests and extending into New Guinea; the cassowaries enjoy the plum-like fruit, although they are not edible by us.
This week I’m highlighting Prunus glandulosa, one of the first Prunus to flower after the official start of spring. It’s one of the smallest of the genus (growing to 1.5 m) and like most Prunus species, contains hydrogen cyanide in the leaves (especially the new shoots), stems and seeds. The cyanogenic glycosides amygdalin and prunasin break down in the digestive tract to form hydrocyanic acid, which in small quantities is good for improving digestion, and is known to give a sense of well-being, but too much cyanide is fatal..
In July I highlighted the Flowering Weeping Apricot, Prunus mume ‘Pendula’, and mentioned P. glandulosa for its short flowering season, and the pruning technique we use of cutting the stems to ground level every year after flowering (known as coppicing). The flowering season is so short because the flowers all open at the same time, and consequently flowering is over in a matter of weeks. Although the flowers are short lived, the plant itself is long lived, and is incredibly tolerant of its annual coppicing. The species is planted in several areas of the Gardens, including the bed in the photo, which shows the Flowering Quince (Chaenomeles speciosa ‘Falconnet Charlet’) in the background. This bed was designed by Burnley Gardens designer Emily Gibson, so likely to have been planted around 1950. Although the combined display is short, the chaenomeles flowers long before and after the prunus, and the simple planting scheme ensures that the maintenance needed to produce such a display is minimal. The deciduous leaves create mulch that takes care of any weeds, and the only other maintenance needed is an annual cut down of the prunus stems and a light prune of the chaenomeles.
Prunus glandulosa, Dwarf Almond, was popular in Victorian and Edwardian times, and was introduced to England from China in the early 1800s. Thomas Moore referred to the white winter-flowering almond in one of his poems, Lalla Rookh (1817), The Light of the Haram. The part of the rather long poem where the almond flower is mentioned seems rather apt this year, as it goes
“The dream of a future, happier hour
that alights on misery’s brow,
spring forth like the silvery almond-flower,
that blooms on a leafless bough”
Andrew’s Plant of the week…….01.09.20 – Edgeworthia chrysantha
Firstly, it’s location in the Gardens, tucked away in the southern corner to protect it from hot dry winds. This area was for some decades referred to as the Winter Garden. The first record of this name was in the 1980s, so it is not a name of long standing*. However, upon a recent re-reading of Principles of Gardening for Australia (1903) by Charles Bogue Luffmann, Burnley’s most influential designer (1897 to 1907), in which he discussed how best to use plants, it became evident that this evergreen corner of the Gardens doesn’t fit Luffmann’s idea of what a Winter Garden, with an emphasis on deciduous plants, should be, so we now refer to it as the Wild Garden. Even the spelling of Luffmann’s name is intriguing: one ‘n’ or two? I chose to use the version with two ‘n’s, as this is how he spelt it himself towards the end of his career.
Secondly it’s intriguing for its specific epithet. Is it Edgeworthia chrysantha, or E. papyrifera? Or neither? If you followed The Plant List, which was the accepted authority of the Royal Botanic Gardens, Kew and Missouri Botanic Gardens for botanical names, then it’s neither of these two, with E. tomentosa their preference. However, people can’t always agree (many would say botanists are among the worst culprits) and also, as we know, timing is everything. In the case of this Edgeworthia species, the name E. chrysantha, (meaning “yellow flower”) was published in 1846 a few weeks before E. papyrifera, so as convention has it, E. chrysantha has priority. E. tomentosa refers to the oldest recorded name for the plant, Magnolia tomentosa, but this has been rejected, probably because not only is it not a magnolia, it isn’t even in the Magnolia family, it’s in the Daphne family (Thymelaeaceae). Note that The Plant List (TPL) has been superseded by Plants of the World Online (POWO), and that is where you will find the name Edgeworthia chrysantha, and all its synonyms. The matter of timing reminds me of when, in 2003, the Friends of Burnley Gardens turned up at Heritage Victoria to register the Burnley Gardens on the register of Significant Gardens, only to be told that the University of Melbourne had submitted their application the previous week!
The third intriguing thing is who the genus was named after (this is known as the honorific epithet, if you want to be proper). It turns out that it was named after (the name honours) two people, the botanist Michael Edgeworth (1812-1881), and also his half-sister Maria Edgeworth, who is credited with educating her younger Irish half-brother. Maria is famous for an 1800 novel Castle Rackrent and also for a charmingly named Dialogues on Botany for the Use of Young Persons (1819), so perhaps Maria inspired and influenced Michael’s botanical wandering and collecting in Yemen, India (where he worked) and Sri Lanka.
Lastly, Edgeworthia is intriguing because of its historic use in Japan, from 1600, as a source of fine paper used for wall paper and bank notes. The bank notes were considered the finest in the world, with exceptional quality, and importantly the most difficult to forge. It is interesting that even though the plant is endemic to forests and shrubby slopes of southern and eastern China, in a wide range of habitats from sandy coastal areas, stream sides and mountain valleys, it is now naturalised in Korea and Japan, because of its paper making qualities, hence it’s other name E. papyrifera, meaning “paper-bearing”. It’s the inner red part of the bark that is used to make the paper – you would need some patience in harvesting it, as it looks a very fiddly job to get a substantial amount from the stems**.”
*Jill thought this name was given to the area by former Head Gardener Sarah Wain, who said it was her favourite part of the Gardens, although at the time its current name ‘Wild Garden’ would have been more apt, as it had fallen somewhat into neglect. It was Sarah who began its resurrection in the days when Garden Week (Now MIFGS) was held at Burnley. Former Gardens manager Phil Tulk remembers gardeners being told by Sarah not to rake the paths, to enhance the wild look, so perhaps that was her name for the area?
Andrew’s Plant of the week…….25.08.20 – Erythrina x bidwillii
If you’re lucky enough to be able to walk through the Gardens at the moment, you will come across a curious sight. Is this a plant? Or a pile of rocks? Erythrina x bidwillii ‘Blakei’ is one of those plants, at this time of year, that only its parents can appreciate. In this case, the two parents are Erythrina crista-galli and E. herbacea.
What a story this hybrid has to tell. It is an Australian world first; the first woody leguminous plant to be hybridized in the world, and likely bred in the early 1840s by a convict gardener, Edmund Blake. Blake worked for the well-known merino wool and grape entrepreneur, William Macarthur, at Camden Park in NSW. Descendants of Macarthur still live at Camden Park today, as does this Erythrina F1* hybrid. It’s also interesting that botanist John Carne Bidwill’s name is linked with this plant. It was named by English botanist, John Lindley, in recognition of Bidwill (1815-1853), who first took the Erythrina F1 hybrids to England in 1843. Over 30 plants have Bidwill’s name associated with them, Araucaria bidwillii and Brachychiton bidwillii to name just two.
Burnley’s Erythrina x bidwillii ‘Blakei’, given its size and slow growth rate, must be nearly as old as the specimens in the Royal Botanic Gardens Melbourne. Ferdinand Mueller (also known as Baron Sir Ferdinand Jacob Heinrich von Mueller), Director of the RBGM, 1857-1873 and Macarthur were great friends, so it’s likely the erythrinas in the Botanic Gardens were a gift from Macarthur; they were also listed in an 1857 plant catalogue. The garden bed at the orchard steps where Burnley’s specimen grows is one of the three original beds planted up in 1861-2, so given how slowly the woody bole (caudex, the trunk from which it re-shoots each spring) grows, it could be part of the earliest plantings at Burnley. It continues to produce two metre long growths each spring, and its brilliant, bright red flowers are produced for six months of the year. It looks particularly spectacular in autumn, when the mass of white Japanese Anemones (Anemone x hybrida) in front of it, are also in flower.
*An F1 hybrid is the first-generation offspring from two dissimilar parent plants. ‘F1’ stands for Filial 1 or ‘first children’.
Andrew’s Plant of the week…….17.08.20 – Aloe ‘Tangerine Tree’
While it’s a little unfair to just single out one of the flowering aloes from the Swan Street beds, this Aloe ‘Tangerine Tree’ needs a special mention for being so striking. Planted at the entrance from Swan Street to the Campus, the multiple flower heads are spectacular even before the flowers are fully open. This Swan Street planting design, including the rock tiers below, were designed by Burnley graduate and current President of the Friends of Burnley Gardens, Sandra McMahon. Whenever I’m up at the Swan Street beds, and happen to see a member of the public walking through the central pathway, it’s always the same, they always comment on how much they love it. Sandra’s inspiration was to use numerous and different aloes throughout the street-frontage bed to ensure there is always one in flower at any time of the year. The majority of the spectacular aloes brought into cultivation are bred in South Africa, by Leo Thamm from Sunbird Aloes and given their drought capabilities, they are well suited to most Australian climatic conditions.
Andrew’s Plant of the week…….11.08.20 –Dodonaea sinuolata subsp. sinuolata.
This shrub is growing in the Kath Deery Native Garden and is one of the originals Kath selected for the beds. Most of the plants she personally selected for the area in 1987 she considered outstanding selections of either their genus or in the case of this Dodonaea, the best dioecious form. While both the male and female flowers are small, and unless you are close up, rather insignificant, once the female flowers set fruit and begin to colour up, the display is awesome. That’s the advantage of taking cuttings, you end up with the best traits the plant has to offer.
The pinnate foliage is reason enough to plant this Hop Bush, with its dark green colour, shiny texture and spicy fragrance providing great foliage appeal. With good frost, drought and light tolerances, plus appealing bark, this shrub has many fine qualities for inclusion in landscapes.”
Andrew’s Plant of the week…….04.08.20 – Clematis microphylla
Andrew comments: “this week’s plant, Clematis microphylla, is a lucky dip, in terms of whether you end up with male or female flowers on the vine you planted. Probably used mostly in re-vegetation, this vine has lots of great features that could enhance any garden, but being dioecious (having male and female flowers on separate plants), you never know until it flowers what you’ll get.
When they do start to flower, my preference would be the male of the species, as it tends to stand out more in terms of flower density and therefore impact. It also doesn’t produce seed, which is good, as the female plants produce prolific wind-blown seed.
There seems to be a slight colour variation of the flowers between individual species, with some being cream coloured, while others are more white.* The male flowers are like little stars and when grown up a branch support can look like a Christmas decoration.
Although its natural tendency in the bush is to climb up and on top of shrubs, it can be easily trained onto fences or supports and also be used as a ground cover. The best flowering is achieved when grown in full sun. This clematis has a high drought and frost tolerance and pairs very nicely with Hardenbergia violacea, as they flower at the same time.
* The Flora of Victoria on-line describes the flowers as having “Sepals white to pale yellow”. https://vicflora.rbg.vic.gov.au/flora/taxon/08d7e9bc-c930-41f1-b06d-e09520b24158
Andrew’s Plant of the week…….24.07.20 – Salvia ‘Fran’s Folly’
Using the common scenario, if you were stranded on a desert island and could only pick one ornamental shrub genus to keep you company, what would you choose? I think Salvia might be one of the most common answers.
The Salvia genus has almost everything you need: there is always one in flower at any time of the year, they come in almost all colours, have a wide range of habits and tolerances, and are one of the easiest to prune. Oh, and insects and bees love them.
A winter flowering salvia I’m highlighting this week is ‘Fran’s Folly’. Grown as a chance seedling nurtured to flowering maturity in the backyard of FOBG propagator Fran Mason, (a salvia lover who had a huge number of them growing around her house) this salvia’s only limitation is in not having a high frost tolerance (perhaps only down to minus 2° – the July frost a few years ago damaged mine at home).
With obvious Salvia parentage of S. karwinskii, and perhaps S. involucrata ‘Bethellii’ as the other, the chance seedling has fine attributes of both. Just as tall as S. karwinskii but with greater flower density, ‘Fran’s Folly’, as Fran called it herself, is a welcome inclusion to the back of a perennial border or even as a feature shrub in its own right.
Andrew’s Plant of the week…….19.07.20 – Alyogyne huegelii x hakeifolia ‘Natalie Anne’
This hybrid cultivar, Alyogyne huegelii x hakeifolia ‘Natalie Anne’ caught my attention in a nursery catalogue, and once I saw a photo of it, I ordered one for the Kath Deery section of the Native Garden. The western end of Kath’s 1987 plantings had become dominated by the rather moisture-and-shade loving Prostanthera rotundifolia, and each hot summer one or more would succumb to the unfavourable conditions, despite being irrigated. So I was on the look out for a plant more suitable to the western aspect, and this Alyogyne hasn’t disappointed.
While A. huegelii is an outstanding species with great attributes, I find it prone to poor branch attachment, with included bark, with the consequence that it frequently falls apart. There are 5 forms of A huegelii, even a lower growing form, so a bit more research would probably prove rewarding for a better outcome.
However, this cross of A. huegelii with A. hakeifolia, for me, is far more reliable, and has wonderful attributes that make it a highly desirable shrub for a western aspect. It needs a bit of space to show off its delicate dark green foliage and this fine foliage and terminal flowers gives the blooms a slightly suspended, graceful appearance. It started flowering in autumn and is showing no sign of stopping. There is no need to dead head to produce more flowers, it does it on its own. Its one of those shrubs that you never really know when to prune, as you feel rather mean cutting it back when it is still flowering.
Andrew’s Plant of the week…….06.07.20 – Prunus mume ‘Pendula’
With so much choice of what to highlight each week in the Gardens, I felt I mustn’t ignore the well-known Burnley specimens of Prunus mume ‘Pendula’ (Weeping Apricot). The glorious, fragrant cascading stems, densely packed with flowers, have been a winter staple of the orchard gate steps for at least 35 years. (At this time of year, in mid-winter, the only other blossom tree in flower is the almond (Prunus dulcis var. dulcis), and its flowers are white, with prominent red stamens.)
When on the rare occasion I’ve seen this tree planted in suburban gardens, it’s a tangled mess of branches, almost unrecognizable as the same cultivar as our trees, apart from the familiar pink flowers. What makes ours so floriferous and special is the way it has been pruned each year. This Prunus species flowers on its one year old wood, so we maximise its flowering potential by timing the pruning to create the longest new, one year old stems. As you can see from the photo taken from inside the cascading stems, the zig-zag branch framework is testament to the long pruning practise we have done, leaving one or two leaf internodes from where it was pruned last year, and pruning to an upper node so that the new growth arches downwards.
Deciduous shrubs and trees have a known strong response to hard pruning in late winter, thus producing the longest stems. As soon as the last petals drop and the first sign of leaf bud burst occur, we will prune the stems and start the process again.
We also do something similar with Prunus glandulosa in spring ( except that we cut these to ground level), but whereas Prunus glandulosa blossom only lasts a few weeks, P. mume starts in late June and goes through to mid August. The secret of this long flowering season is the succession of flower buds opening, so if, like last weekend, heavy rain destroys the flower display, there are always more flower buds to open, ensuring a constant blooming feast.
PS don’t forget to click on each image for a bigger picture!
Andrew’s Plant of the week…….06.07.20 – Auranticarpa rhombifolia
Anyone who walks past, or views this small tree from the staff room can’t fail to notice this orange splash of colour. Previously part of the Pittosporum genus, the northern NSW and Queensland Pittosporum specimens were deemed sufficiently different to justify their own genus, Auranticarpa. (2004, 3 of the 6 species were new).
This rainforest tree is a bit out of its comfort zone down here in Melbourne, which is probably why I haven’t seen too many in cultivation (RBGM has it, of course), and I must admit, before the installation of irrigation, it was not performing anywhere near as well as it is now. It definitely needs summer irrigation, to replicate its northern Australian habitat, to produce abundant fruit capsules.
As it is at the back of the bed, on the east wall of the Plant Science building, I haven’t really noticed the small fragrant flowers that are produced from spring to autumn, its extended flowering probably taking advantage of constant moisture provided by the irrigation. This extended flowering season results in a great assortment of fruit size, from large to just developing, which gives the tree a long display period for most of the year.
For a plant that produces so many fruit/seeds, you’d think that like its relative Pittosporum undulatum, it might be very weedy. Perhaps the long germination period needed* and colder southern temperatures deters it, or perhaps the seeds are not as sticky as those of P. undulatum, which is spread so widely by birds.
For a plant we never have to maintain, requiring no pruning, it certainly provides great value, although I notice in my photo that there are some scale that need attention. These two specimens were planted several decades ago, in the mid to late 80s, having been introduced to the Gardens by then lecturer James Hitchmough, who taught it to his Plant ID students in 1986 as an Australian plant that provides autumn colour. They seem long lived and a great survivor of a previously un-irrigated bed dominated by the Eucalyptus tricarpa, but are unlikely to reach the size they do in their northern habitat, where they can grow as tall as 25m.
Plant of the week…….30.06.20 – Montanoa bipinnatifida
A well known sight for visitors to the Rose Garden in winter is Montanoa bipinnatifida. This tall and imposing daisy hails from Mexico, where it has a range of habitats, including roadsides, riparian, and hillsides in the diverse Pine-Oak forests region.
This high altitude forest straddles the Tropic of Cancer and is climate temperate with summer rainfall.
Although planted in a protected spot, the specimens in the Rose Garden, even with their large leaves, don’t seem to scorch in high temperatures or suffer drought stress in Melbourne’s dry summer conditions. Another adaptable species that seems to defy the odds.
The foliage alone is reason enough to plant this towering daisy and at a time of the year when the roses aren’t flowering, this plant provides a dramatic feature.
Plant of the week…….22.06.20 – Hypoestes aristata
A welcome bright surprise during the long winter months is this purple flowering Hypoestes growing in the understorey of the Ficus bed. The colour of the flower in this photo is more pink than the purple it really is, so worth taking a look for yourself to get a better idea of the flower colour. This lower growing cultivar of the species was developed in South Africa at the Witwatersrand National Botanic Garden after selecting from the usual lilac-purple, pink and white larger forms.
This species is well known and appreciated in South Africa for its long winter flowering and drought and shade tolerance. It’s also reported to be eaten like spinach in some areas, http://pza.sanbi.org/hypoestes-aristata , although as it is a member of the Acanthaceae, it doesn’t sound very appealing to me. It is an excellent cut flower, lasting well in a vase. I first saw this plant in coastal NSW and brought it back to Burnley to propagate. It took a fair bit of identifying, but as usual, Jill Kellow worked it out.
Note from Jill: It took a while though – I first saw this plant at RBGM on Wednesday, 15 August 2012, and didn’t know its name for several years. It was the amazingly vivid colour that caught my eye.
P.S. Isn’t it handy that we can check the date of our digital photos?
Plant of the week…….17.06.20 – Hakea multilineata
A beautiful shrub demanding your attention at this time of year is Hakea multilineata. Unlike many of the spectacular Western Australian hakeas, (such as Hakea bucculenta or H. francisiana), this species doesn’t require grafting onto an east coast rootstock to survive. Despite the flowers being within the foliage, its open canopy allows the flowers to be well displayed, and prior to being fully open are, I believe, even more spectacular. We can thank Jeremy Wallace, Burnley’s nursery manager in the ’90s and 2000’s, for this addition to the Gardens. Jeremy had (has) a special knack of tracking down unusual native plant seed, and great skill in germinating and growing-on these native gems. Once he had them established in pots he’d offer them to the Gardens, where we’d find a spot for them to grow. All of the plants he gave us needed no irrigation to survive and were always unusual and in one case endangered in the wild.
Plant of the week…….10.6.20 – Iris unguicularis, ‘Kilbrony Marble’
Andrew tells us how he obtained this Iris cultivar, which is special in more ways than one: “a beautiful variant of the often sneered at Iris unguicularis, ‘Kilbrony Marble’, is currently in full display in the gardens. What make this variety so special are the exquisite streaks of purple that festoon the petals. While the species flowers for just as long, March through to September, ‘Kilbrony Marble’ has lower, shorter foliage, so the flowers are far better displayed, unlike those of the species, that are often hidden among the long, strappy leaves.
Drought and shade tolerant, (although will flower better in full sun) this is one of dozens, if not more, of introductions created by the legendary Northern Ireland nursery, Slieve Donard Nursery. This nursery was renowned for its dwarf Dierama and cold tolerant Escallonia cultivars, but sadly, many of its cultivars are now extinct.
I obtained Burnley’s ‘Kilbrony Marble’ from Geoff Olive, from his property in Buxton before he passed away in 2016. I was like a child in a candy store up there, running around Geoff’s garden exclaiming “wow, what’s that!” I took quite a few cuttings of various “eye candy” specimens, and they now hold pride of place in various spots in the Gardens.”
Plant of the week…….2.6.20 – Luculia grandifolia
Andrew says: “While we tend to swoon over Luculia gratissima, especially at the start of winter when the fragrant pink blooms take our eye, the often underrated L. grandifolia is still covered in flowers and just as fragrant. Whereas the flowers of L. gratissima are all over in a month, L. grandifolia starts flowering in summer, and goes all the way through till early winter. It’s only drawback is no real fault of its own, coming from the Himalayas, (Bhutan) it doesn’t tolerate high ambient temperatures, something the lowlands of Melbourne experiences each summer. With only a few over 38 degree days last summer, the foliage of L. grandifolia is looking better than usual and the flowers buds continue unabated.”
PS don’t forget to click on the image for a bigger picture!
Plant of the week…….27.5.20 – Clinanthus incarnatus (yellow form)
Andrew says: “Continuing on from my recent lime green/yellow plant posting, another in a similar vein is this South American bulb, the yellow form of Clinanthus incarnatus. This bulb was donated to the gardens by Fran, after I inquired if she had anything suitable for inclusion in the green border. Fran’s involvement in the Friends prop group is legendary and her broad knowledge of plants, especially Salvias, and her ability to source them, was a great resource for me to tap into. No sooner had I requested a green flower to include in the re-instated green border, (after the orchard gates were re-aligned in 2013) Fran came up with this unusual bulb.
The large flowers are well displayed above the blueish-green foliage and it’s amazing to think how adaptable this species is, considering its native habitat is rocky soils at high altitudes in the Andes. (Ecuador to Peru)
Plant of the week…….23.5.20 – Schinus molle, lime green form
A recent addition to the tree collection at Burnley is this grafted lime-green coloured Peppercorn Tree.
Burnley has been very fortunate in recent years to have David Beardsell’s grafting and plant breeding expertise to provide drought tolerant tree species for the Gardens. His keen eye while travelling into the city on the eastern freeway spied this lime green foliaged variant of the usually dark green Peppercorn Tree and while his wife wasn’t so inclined to stop for him collect the scion material, he succeeded in persuading her that this lime-green form was worth the risk!
Left: typical dark green foliage of Schinus molle; right: young grafted lime green form. Note: could this be a new cultivar – Schinus molle ‘David Beardsell’?
Plant of the week…….18.5.20 Kniphofia ensifolia subsp. autumnalis
Andrew says: “I’ve wanted to ID this poker for a while. The original clump was at the end of the Bergenia Walk bed, on the pond side of the path. I moved some into the perennial border a few years back; like previous Gardens Manager Phil Tulk, I rather like lime green flowers.
In previous years, it always tended to start flowering in March; in this wetter year it is later: the perennial border flowers are almost done, while the Bergenia Walk clump is just starting.
This lime green poker, that turns yellow as the flowers age, is more uncommon than the red flowering form we all know so well . While the smaller-growing green flowering cultivar ‘Lime Glow’ has been popular in recent years, this Kniphofia subspecies, although not flowering for as long, is a welcome sight in autumn. While the natural habitat is waterlogged soils along the edges of south African streams, this plant has good tolerance for drier conditions. Nectar feeding birds and insects are attracted to the flowers. Don’t forget to click on the image to see the full size!
Plant of the week…….10.5.20 Camellia sasanqua ‘Momozono”
From Gardens Manager Andrew Smith: “Thanks to Jane for pointing out that the correct cultivar name for the Camellia sasanqua cultivar that I posted recently is ‘Momozono’ rather than ‘Plantation Pink.’ The FOBG Guides in 2006, in particular Julie-Anne, did some great detective work in tracking tracked down the correct name for this erroneously named cultivar (it was labelled ‘Noma Goma’ in the Gardens). It seems I should place more credence on our own Guide It seems I should place more credence on our own Guides expertise than the International Camellia Society’s images that I based my identification on.
Plant of the week…….1.5.20 Lagerstroemia fauriei ‘Fantasy’,
Some lovely autumn foliage is happening at Burnley. This more uncommon Crepe Myrtle, Lagerstroemia fauriei ‘Fantasy’, with its orange autumn colouring, is complemented well with the red Boston Ivy (Pathenocissus tricuspidata) behind it. Click on the image to see the full size!
Find out what was happening in the Gardens back when ….