Sunday, December 9, 2012


Picris evae

I can’t see this plant ever being particularly popular in gardens, but I’m sure you’ll agree its fluffy heads give it a ragged sort of charm. These plants are in my garden (which has its own brand of ragged charm) and are looking their best at present, having been planted last autumn.



It is an annual plant, belonging to the branch of the daisy family which includes dandelions and lettuce.There are 12 Australian Picris species, and about 40 of them worldwide, including the European  Oxtongue hawkweed Picris hieracioides - originally named for the ancient Greek words pikros "bitter" (for the flavour of the roots and leaves) and hierax "hawk", because it resembled another European plant known as hawkweed. 

If you hear of "hawkweeds" as environmental problems in Australia, it refers to these OTHER hawkweeds, (Hieracium species), not to Picris. (Here's another case where a bit of discrimination in applying common names would be a great help to ordinary people understanding of our wild plants!)

Meanwhile, our local "hawkweed", Picris evae, is now so rare that’s listed nationally as vulnerable. Its natural range coincides largely with the cultivated areas of our black soil plains, which is the reason is getting hard to find. However, it does also occur naturally in grassy Eucalypt woodland along the edge of the range, on red soil, where “inappropriate fire regimes” are listed as a threat to it.
This is a reminder that a significant portion of our local ecology developed as a result of many thousands of years of consistent management by Aborigines, who used fire as a tool to shape the landscape of their homeland to suit their needs. The burning was far from random or ad hoc. Burning at the right time (whenever that is) is good for this plant. Lack of burning, too-hot burns, or erratically timed burns are bad for it.
Unfortunately, the detailed knowledge of how to manage our local fire ecology has been lost with the people who held it.

Friday, November 30, 2012

Black Bean

Castanospermum australe

It takes a few years to see a reward, when we plant rainforest trees, but black beans are among the ones which put on a good show while still quite young. This lovely specimen in Highfields has been flowering for several years now. I don’t know it’s age, but it’s probably about 10 years old. The species is great value for a larger garden. It will grow quite fast to make a medium to large tree - about the size of the familiar camphor laurels, which are used as street trees in Toowoomba. It's dense, dark green canopy makes it a very good shade tree.

 The flowers appear on old wood, inside the canopy.

Flowers at all stages of development are on the tree at the same time, and make a perfect illustration, if you happen to be wanting to teach children how flowers “turn into” seeds.

These little green pods will develop into large brown seedpods, whose huge seeds will germinate if left sitting on damp soil in a pot - another interesting thing for children to see. They can use the pods as boats, once the seeds have been taken out. The circular depressions left by the seeds make good “seats” for tiny toys.
The special shape of the flowers shows us that the plant wants to attract nectar-eating birds as pollinators. The jacaranda in the background (an introduced tree, native to Amazon rainforests) has very little appeal to wildlife. The black bean, however, is pulling its weight as an active contributor to a healthy suburban environment.
It is drought hardy in the Toowoomba area, and tolerates light frosts.
For more on this plant, see Nov 2009 (or use the “search” box, at top left).

Black-fruited Sedge

Cyperus tetraphyllus
Plants’ scientific names can be as unsatisfactory as their common names. “Tetraphyllus” means “four leaves”, but this is obviously not a four-leafed plant.

I wonder whether the name might have been a reference to the leaf-like bracts that surround each seed-head. Perhaps the first plant examined seemed to be consistent in having four of them?

In practice, though, they can have anywhere between three and six bracts. In this plant, which I grew from seed at home, they consistently have five, of varying sizes.

Isn’t it a lovely, spiky-looking thing? The spikes are soft, though, and don’t prickle the legs of passers-by.
In the wild, this plant is found lining the edges of shady rainforest paths. When not in seed, it resembles the introduced plant, mondo grass, and would make an excellent native substitute for it. The lovely seedheads are a bonus.
It is easily grown from seed (as are all our native sedges), but can also be purchased from specialist suppliers.
It is somewhat drought tolerant (growing naturally in Goomburra National Park), but probably won't tolerate frost.

Thursday, November 15, 2012

Split Jack

Capparis lasiantha
   We rarely see these plants on the eastern side of the Condamine. I found this one in Edgefield Road North-east of Dalby, where the basalt soil is blending into sandy alluvial soil.
   Like our other local native capers, it has flowers which resemble butterflies, with its four petals arranged in pairs.
Also like other native capers, the plant is well-defended by ants. (I can find no information about this well-known association between ants and Australian Capparis species. I imagine that they are being attracted by nectar-secreting glands (nectaries)  that have evolved for the purpose. Can any of my readers enlighten me?)
   The flowers of most of our native capers are short-lived, losing their petals by mid-afternoon. Their decorative qualities come from the sheer quantifies of flowers produced. However these little ones were still hanging on, quite late in the day. They seem to open white and turn yellow, but I don’t know whether they last for more days than one.

   Split Jack is a scrambling climber, hanging onto its host plants by the sharp little pairs of spines at the base of each leaf. Some capers lose their thorniness as the plants age, but this one seems to be a thorny little devil all its life. (Now there’s the thing to grow on a fence, if you’re worried about prowlers!)
   They can climb to about ten metres, but are more often seen on fences where they can grow quite bushy, or scrambling over themselves to make dense, bird-sheltering shrubs. They grow densely without pruning, but are happy to be confined to a desired shape and size with the secateurs.

Like all Capparis, they are hosts for a number of butterfly species, like this Caper White (Belenois java).

Grow a split jack, (or a native caper of any kind) and you will always have native butterflies in your garden!

Short-Jointed Mistletoe

Korthalsella taenioides
(Korthalsella breviarticulata)

A roadside stop to look at some flowering Capparis lasiantha last week,  in Edgefield Road near Dalby, was particularly rewarding.  I also found this perfect little mistletoe, growing on the caper plant.

Isn’t it a darling little thing?
The whole plant is about the size of an orange - which is as large as it gets - and it is fruiting very prosperously, as you see.
Apparently these seed capsules are weakly explosive, likely to burst, spraying out their sticky seeds, when touched. It’s thought that the plant spreads on the birds’ feet and feathers.

Korthalsella species are the only known host plants for the Yellow-spotted Jezebel butterfly, so the survival of this little plant is important to them.

It is known to grow on a wide range of dry rainforest species, including Alectryon diversifolium, Geijera parvifolia, Melodorum leichhardtii, and various Capparis species, and can probably be transferred to these plants by hand. Paople who want to attract these butterflies to their gardens might like to attempt it, in summer when seeds are ripening.
(Like all seeds, mistletoe seeds and seedlings like to be watered until they are established.)

Thursday, November 1, 2012

Scrub Whitewood

Atalaya salicifolia

I found this delightful little whitewood tree beside the New England Highway, north of Crows Nest, last weekend. It is flowering its little heart out.

 Left to reach its potential, it will grow to be a shady small tree with a trunk 30cm in diameter. Typically of many plants of our dry rainforests and vine thickets, it is suitable for growing in small gardens, or as a street tree.

By summer, its flowers will develop into bunches of brown, winged seeds.

Whitewoods are decorative from an early age, because of their interesting juvenile foliage.  
The leaf shown below is from a young plant 1 metre high. Note the winged rachis .

This more mature leaf came from the young roadside tree shown above. It has intermediate foliage - leaves broadening out, and the rachis-wing narrowing.

In older plants, the rachis disappears altogether, but the prominent swellings (pulvinules) at the base of the leaflets remain, helping us to identify the tree.

It is drought hardy, but tolerates only the lightest frosts when it is young.

Thursday, October 25, 2012

Red-fruited Palm-lily

Cordyline rubra
It's flowering time for our little native palm-lilies.

 They are ideal plants for a shady garden, because they will flower in situations where light levels are low.
At no more than 2m high,  these plants are ideal for modern suburban gardens or courtyards. They are effective against a light-coloured wall, where their sculptural lines go well with modern architecture.(This photo was taken at the new Maroochy Botanic Gardens last month.)

They are also good tub plants, and grow well indoors.

Originating in our local rainforest understorey, they are perfect for growing under trees, where their foliage adds to the cool green effect. Subtle highlights are provided by the generous panicles of lavender flowers in spring,  and splashes of brilliant red long-lasting berries in summer.

These frost tender plants grow well in Toowoomba gardens, on red soil.  Like most of the plants of our local rainforests, they are "waterwise" plants, surviving our toughest droughts once established, provided they are situated in full or part shade. 
They will tolerate fairly sunny conditions, if given supplementary watering in dry times.

Another local palm lily is the larger Cordyline petiolaris. For more about it, see articles July 2009, and Nov 2009 (Ravensbourne).

Thursday, October 18, 2012

Silky Oak

Grevillea robusta
The silky oaks are just beginning to come into flower.
We can expect to see them continue their spectacular display for much of November.

With a bit of careful planning they can be among our finest landscaping trees. Not suitable for small gardens, they are best used for acreage, highway, and park planting. They also make very good street trees - provided the streets are rather roomy. They co-ordinate wonderfully with the scarlet flowers of the flame trees (Brachychiton acerifolius), another spectacular local native plant that flowers at the same time.

Silky oaks are fast-growing and live for 100 years or more. They are drought hardy, and cope with frost to -4° even when young.
However, their large, shallow roots can be problem,  interfering with built structures, and travelling a long way for water. Ideally, the trees should be should be planted 5 metres away from concrete footpaths and 15 metres from underground pipes.

 They are deciduous in spring, with new leaves appearing as soon as the old ones fall. The impression given is that the younger generation are pushing the oldies off the tree.
The fresh leaves are a pretty shade of green, with silverybacks that show off in the wind.

In this country where deciduous plants are not common, trees which dump all their leaves in one go are regarded by some people as too messy for words. However, they do provide a wonderful “mulch opportunity”, especially as the intricate shape of the leaves means they don’t tend to blow all over the place, like the leaves of some other deciduous trees. Once positioned as mulch they tend to stay put. (I  pick them up from the lawn with a mower, and use the nutrient-rich grass and leaf mix on the garden).

Silky oak flowers are fascinating.

Each flowerhead might have as many as a hundred small flowers. At first glance, each one seems to consist of nothing much but a long style. This is the female part of the flower. The little green knob at the end is its stigma. It’s eventual female role is to catch pollen and pass it along to the ovary, a second little swelling lower down on the style, where the egg cells await fertilisation by the pollen.
New flowers are functionally male. The style is curved in a loop, and the stigma - not yet mature and sticky - is held firmly in a socket formed by the tip of what looks like a single little petal. As the flower begins to mature,  the “petal” breaks up into four tepals, and the four pieces of the opened-up socket are each revealed to have an anther on the inside.  This is the male part of the flower, now mature, producing pollen, and firmly in contact with the immature stigma.
The style straightens out, revealing the pollen-covered green knob of the stigma. At this point the female part of the flower is unable to be fertilised, and simply acts as a pollen presenter. It holds the pollen out there where it will rub off on the feathers of visiting birds which are attracted by the copious flow of nectar that each flower produces at this stage of its maturing process.
As the birds move around feeding on the flowers' sweet bait, the they carry the pollen about with them, much of it reaching stigmae of flowers which are at a later stage of development. The male part of those flowers has retired. It no longer makes pollen, and the flower is now functionally female. The stigma is now sticky and catches pollen from passing birds. Some of it makes its way down a pollen tube to the flower's ovaries.

 This photo shows the three stages of the flower. (Click to enlarge for a close look.) In the first (male) stage, the stigma is head-down among the fertile anthers, being dusted with pollen.  In the middle stage, the style has straightened out, and the stigma is liberally coated with pollen, presented ready for birds to take away.  In the last (female) stage, the stigma has become sticky and is ready to catch pollen and pass it down to the ovary. When  fertilisation has been achieved and the tepals fall off, the style begins to shrivel and the ovary swells to become a seed capsule.

The photo above shows a flowerhead fresh with newly opened flowers. Click to enlarge, to see the generous nectar flow that has suddenly appeared at the base of the styles. The tepals are clearly marked with red nectar guides, advertising its presence to the mobs of shrieking birds which descend on the trees for the feast.
The result is that pollen is scattered about rather wildly. Some pollen grains stay close to home, fertilising more mature flowers from the same tree. Some is spread to other plants. Grevilleas are well-known for their ability to cross-pollinate, even between different species.
In the old days, Aborigines used to make a sugary drink from silky oak flowers, dipping the whole flowerheads into water to wash the nectar off.
Silky oak timber is among our finest of cabinet timbers, with its warm honey colour. It is usually quarter-cut, to show off its silky rays.

Grevillea robusta and Allelopathy
Silky oak seedlings don’t thrive under parent trees, and it may be that they are suppressed by an allelopathic chemical produced by their roots.  I notice that many overseas internet sites claim that Grevillea robusta’s allelopathic effect kills off “the saplings of all other species”. This doesn’t seem to be the case in my garden or in our local rainforests.  In both cases it grows in close harmony with other plant species.
Claims about the allelopathic attributes of various plants are rather fashionable at present. In some cases they are true. In others, they are premature, the scientific research having not been done. Fast-growing trees can also suppress other plants by more efficient use of the available soil nutrients and water, and by shading them out with their canopies or their carpet of mulching leaves. This may be the real cause of some of the sweeping accusations of allelopathy. (An allelopathic plant usually has a different effect on different plants, with some species being suppressed, while others are actually improved.)
It wouldn’t surprise me, however, to hear that silky oak allelopathy suppressed other Proteaceae, and some research showing that it suppresses wheat may also mean that it suppresses grass (though I find that kikuyu grows well around the base of one of my trees).
I would be interested to hear from my readers about their experiences with growing plants near silky oak trees.

Saturday, October 13, 2012

Spear Lilies

 Doryanthes palmeri

The Spear Lilies growing on Mt Cordeaux are one of the natural wonders of our district - and the time to see them is now.

Hundreds of these spectacular plants , with their “spears” of bright red flowers, spread down the eastern escarpment. Growing with them are grasstrees, Xanthorrhoea glauca.

   Following the path on  the western side, we can get up close and personal with the huge flowerheads, which are often more than a metre long.

Butterflies and  European honeybees were attracted to them. The butterflies would be attracted by the red, as they are some of the very few insects that can see that colour. It would be interesting to know just what the honeybees can see. They were certainly guzzling on the nectar, fighting over the newly opened flowers.

Birds can see red very well, and it is often the case that big red flowers are designed to attract them as pollinators.

Yesterday a group of these Lewin’s honeyeaters were taking advantage of the nectar flow. There was quite a party atmosphere as they socialised, flirted, and flew back and forth between the lilies and the overhanging trees.

Mt Cordeaux is about an hour’s drive from Toowoomba. Heading east on the Cunningham’s Gap Road, it is the mountain on its left-hand side, just before the road heads down the eastern side of the Great Dividing Range. Access is from a small carpark in the Gap.

Saturday, October 6, 2012

Chamomile Sunray

Rhodanthe anthemoides
I had a delightful visit last weekend, with family, to the Darling Downs Zoo.
I enjoyed the lions and the monkeys. I loved the way that the beautiful red-rumped grass parrots, which are natural to the area, were thriving because they can zip in and out of the cockatoos’ cages and steal the seed. I also enjoyed the native spring flowers which were popping up in some of the animal enclosures.
I photographed these little sunrays near the fence on the road outside. They looking particularly lovely with their gleaming white beside the blue of the native bluebells, and the brilliant red of the local Darling pea. (See "It's Wildflower Time, Oct 2011)

They are paper daisies. Sometimes they persist for a few years, but I find it best to treat them as annuals, and they are a local plant with very good potential as bedding annuals.
Wouldn’t it be refreshing to see some beds of them at Toowoomba’s Carnival of Flowers?

Seed will begin to be ready in the nest few weeks, and the best seed is that picked early in the season. Freeze it overnight to kill the bugs, then keep it until March, for planting. I prefer to start seedlings in the shade house and then plant them out, but have also had success with just scattering the seed of this frost hardy plant about in the garden.

The same species can be bought in nurseries, but I have found the local plant to be hardier here, needing no watering once established. It is more upright than the commercially available plant, growing to about 20cm high.

The flowers can be dried and used in floral art, just like the other kinds of paper daisies.

Friday, September 28, 2012

Native Wisteria

Callerya megasperma  (Milletia megasperma)
Just as those glorious, non-native wisteria are coming to the end of their flowering period, the native wisteria  is starting to open its softly furry white buds.
Like the introduced plant, this is a large woody climber, needing a strong fence, a sturdy pergola, or a large “wheel” on a post,  for its support. It also has large panicles of flowers, though does not produce quite such a generous display of them.
Unlike the introduced wisteria, this is an evergreen plant which keeps its glossy green leaves all year round. The stems of young plants are particularly beautiful, with their peeling bark.

 The flowers are interesting, in that the reproductive parts are clearly visible. Note here the female part, the long slender style topped with a little stigma, and the male parts, the stamens, each with a pollen-producing anther at its tip. The anthers of this flower are joined together at their bases.

Native wisteria flowers are rather unusual. Flowers of the pea family typically hide their reproductive parts between the petals of their keels, and have a high rate of self-pollination. This flower clearly wants to get its pollen out there, and its stigma is firmly placed where it will receive pollen transported from another flower, when it is visited by its nectar-seeking pollinator.

Here’s a detail I didn’t notice until I had this photo up on my computer!

It’s a butterfly caterpillar, from the family Lycaenidae. These butterflies have a symbiotic relationship with ants, which protect them in exchange for sweet juices, which the caterpillar exudes. I'm not certain which species of butterfly this one is, but it may be a pencilled-blue (Candalides absimilis). (This is a species known to breed on Callerya. and the caterpillars seem to me to look right.)

The plant will have  has a second ornamental feature around Christmas time, producing large, woody seedpods, which look as though they’re covered in soft green corduroy.

Native wisteria is a plant of rainforests which grows happily in Toowoomba gardens, tolerating light frosts, and needing no extra watering in our climate.

Friday, September 21, 2012

New England Daisy Bush

Olearia canescens
Here’s a plant that we don’t see much of, yet it was probably once quite common on black soil hills on the Darling Downs . It’s a pretty, waist-high, daisy bush, also known as “grey daisy bush”, because of its soft grey-green leaves.

I photographed these flowers, from a bush which has almost finished flowering for the year, on a roadside at Silverleigh, near Acland.

The plant (hard to photograph among other plants) had obviously flowered profusely, so when a friend told that it grows easily from cuttings, I took some home to try, as it makes a good garden plant.She has one in her garden, where it fills a space more than a metre wide, and says it is best pruned each year after flowering, to help it keep a neat shape.
I took these photos of the same species at Tregole National Park, out near Morven, last month.

This is a drought resistant, frost hardy plant.

Saturday, September 15, 2012

Grow Me Instead

Here’s a great website. Have you had a look at it?
To find the Darling Downs Section, click on the map of Queensland and go on from there.

Narrow-leafed Croton

Croton phebalioides
I was shown this lovely stand of old-growth shrubs last weekend, at Silverleigh (near Acland).

As the photo shows, they were growing on a basalt scree-covered hillside. It was an eastern slope, which I suspect would be a favourite habitat, as this plant likes to be sheltered from wind and sun when it’s young.
Usually found on the western side of the Great Dividing Range, this aromatic, grey-foliaged plant is a cousin of the better-known silver croton, C. insularis.

Like that plant, its leaves have silver backs, which look lovely blowing in the wind. Also like the silver croton, each leaf turns a startling shade of orange before dying and hangs on for some time. The plant is ornamented with bright flecks of colour almost all year round.

This plant was in bud. Flowers and the fruits are inconspicuous, but much appreciated by wildlife - particularly birds, which eat the seeds.

The top photo illustrates the plant’s natural, unpruned shape, when grown in the open. I have never seen it used in a garden, but suspect that it would make a very good, waist-high hedging plant.
It is fast-growing, very drought hardy, and (considering its natural habitat), probably tolerates at least light frosts.
For more on Croton insularis, see articles July and Dec 2009.

Those Mysterious Leaf-glands

We are all aware, (at least I think we are), that plants produce nectar in their flowers to attract pollinators. These are usually insects, though some plant species use birds or other animals.
The glands which produce it are called nectaries. They are surrounded by a beautifully engineered arrangement of petals, designed to ensure that only those capable of carrying pollen to other flowers can reach the nectar - and then only if they align themselves just as the flower requires. (Flowers are bossier than you'd think!)
This means that the pollinator body-part, which gets dusted with pollen in one flower, will then be correctly positioned to deliver it to the appropriate bit of the next one. It has to be deposited on the stigma, to do the job of fertilising the flower’s future seeds.
Somewhat less known, however, is that plants have other nectaries which are open to all comers. They are called “extra-floral” nectaries - “extra” as in Latin for “outside”.

They can be on various parts of the plant, but a common position is at the base of the leaf. Croton species provide a good example, with their little glands visible to the naked eye (provided it has good eyesight, or has its specs on). Here they are on Croton phebalioides...

 ...and here on Croton insularis.

Such an easily accessible source of highly nutritious nectar could be found by all sorts of tiny creatures, but a common result is that the fiercest will discover it and keep it for themselves,  chasing away (or eating) potential rivals. In this way, the plant attracts protectors, usually ants, which help to keep it safe from other little sap-sucking, leaf-biting creatures.
Isn't that just so knacky?

Saturday, September 1, 2012

Toowoomba’s Oldest Tree?

Ficus rubiginosa  (Ficus obliqua var. petiolaris)
Toowoomba botanist John Swarbrick has drawn my attention to this magnificent tree. It is a “Scrub Fig”, and can be found in Meredith Crescent.  
 This part of Toowoomba was once part of the garden of Carl Hartmann (1833 - 1887), a noted Toowoomba botanist, explorer and nurseryman who is now best known for his involvement in the establishment of our city’s original Botanic Gardens in Lindsay Street.
Hartmann cultivated 22 of his 40 acres, creating a magnificent garden of his own which contained plants from all over the world. It became a favourite destination for Toowoomba’s weekend picnickers. There was even a bus service which brought people from town for their pleasant day out. Some of the specimens he planted can still be found in the streets and private gardens in that part of Toowoomba.

The fig is an unusually large one of its kind, so it’s more than likely that it was a mature plant at the time Hartmann cleared the land. Much change has happened around it, including a lowering of the soil level. The tree still stands on a mound which would have been the original height of the ground.

Growing in the tree are several large, old blood vines Austrosteenisia blackii. Which probably also pre-date European settlement of the area.

Most of their little leaves are up in the canopy, mixed with the larger leaves of the fig.

However the odd few sprout lower down, and have enabled us to identify the vine, which still grows naturally in Redwood Park, and may have once been common in the Toowoomba City area itself.

Blood vines produce large panicles of deep red flowers in late spring. They would be a sight worth seeing, on such a large vine as this one. We must keep an eye out for them!
Meanwhile, the tree is producing a large crop of figs, which will provide a feast for our native birds.