Thursday, January 28, 2010

Making small trees out of large ones

Pink Bloodwood
Corymbia intermedia (Eucalyptus intermedia)
These lovely trees are flowering all around the district at the moment, and attracting honeyeating birds, butterflies, bees and sundry other insects with their heavy, honey scent.

This particular specimen has been coppiced - i.e. cut off at the ankles. I would estimate that the original trunk was about 50cm diameter. Regrowth has given it these seven sturdy trunks, and the result is a tree that is less than half the height of a single-trunked specimen (see photo below). This is a good way to treat any gumtree that is getting too large for its situation (and a way to have a “cut-and-come-again” firewood supply). If you want to try it, a good height to cut is about 15cm from the ground.
The Corymbia species, which include the bloodwoods and the well-known spotted gum, were once part of the genus “Eucalyptus”. They have now been separated out into a genus of their own, and can be distinguished from true eucalypts by their flowering habit - the flowers are clustered showily on the outside of the canopy, instead of being down amongst the leaves. Locally, gum-tree-like trees which flower like this are either Corymbias or applegums (Angophora species).
Pink bloodwoods are common trees on our local red soil. Koalas eat the leaves, and this is considered to be an important food tree for greater gliders. These lovely animals only eat the leaves of one or two tree species in any given area, so are very vulnerable to the loss of habitat. We could be replacing this habitat, especially in acreage gardens, but, alas, non-local Eucalyptus species are so much easier to buy in local nurseries.
Pink bloodwoods are ornamental from an early age. They are well-shaped trees, and flower from an early age - well worth seeking out.

Common milfoil

Myriophyllum simulans
These must be some of the smallest flowers in my garden. (The leaves are 1cm long).
The belong to a little milfoil, one of the plants which would have been common in the swamps and waterholes of our district before white settlement.
These are fast-growing ornamental plants, much used in aquariums where light levels are high. Though native to Australia they have been exported to America, where they are sold as “frill foxtails” or “filigree myrio”. I hope they do the environment over there no harm. The same trade has introduced two horrors to Australia - the South American M. aquaticum and the Eurasian M. spicatum are two milfoils which should never have been allowed into Australia, where they are now invasive weeds, choking dams, rivers, and irrigation channels. There seems to be no excuse for it, when we have several attractive native milfoils which serve the purpose perfectly well, looking pretty in aquarioums and giving fish something to nibble on and somewhere for their babies to hide.

Milfoils are curious plants. They grow in still shallow freshwater, and during winter they live under it. They can only flower out of water, though, so when summer comes, they put up their heads, grow a different (simpler and tougher) kind of leaf, and pretend to be little Christmas trees. They produce their flowers - first the females, then the males higher up the stem. As their seeds begin to develop, they sink below the water again for the winter.

In the photo at right there are two stems from the same plant - one from underwater and one from above.

Like so many of our native plants, these milfoils are adapted to our unreliable climate. They can survive with the whole plant out of the water, provided the mud they grow in doesn’t dry out.
Most of the world’s Myriophyllums are native to Australia and China, where they are regarded as valuable food for pigs, ducks and fish. They are all medicinal plants, and have another unexpected use - for polishing wood.
They are also highly regarded as water-purifying plants. For this use, they should be harvested regularly. Removing the plants from the water is the final step in any water-purifying process.

Saturday, January 23, 2010

My bladderworts are flowering beautifully

Utricularia exoleta (Utricularia gibba subsp. exoleta)

- and no wonder! Look at the big fat bladders.
In winter, when there’s not much prey to be caught, these bladders are pale green and translucent. The plants are green, so presumably get some of their nutriment from sunshine as well, and I suspect they need this to get them over the winter. When the bladders start to turn black in spring, I know that they’re beginning to find tiny insects to eat. Many of these are probably newly hatched mosquito wrigglers, as the water remains completely mosquito-free.
Once the bladders start to fill, the plants start to flower. It takes a few months for the plants to get enough energy from their summer food source to produce a display like this, which then continues until autumn.
I have often given bits of this plant (whose botanical name is Utricularia exoleta) to friends, who seem to have a high rate of losses. I don’t know why, but suspect that chlorine wouldn’t do them any good. Town water might need to be boiled, and perhaps also allowed to sit for 24 hours afterwards, to make sure the chlorine has all evaporated away, before being poured onto the plant.
I have had losses myself when transferring plants to water in the shade, though a pot of well-established bladderworts seems to be able to live, in the long-term, under the eaves.
See article November 2008, for more on these interesting plants.

Friday, January 22, 2010

Yellow Rattlepod

Crotalaria mitchellii

Crotalarias are plants of high summer, just starting to look their best now.
With a lifespan of just a few years, these are pretty, drought-hardy plants, suited to sunny flower gardens. They are easy to propagate from seed.

These showy spikes of bright yellow pea-flowers are followed by inflated seedpods. As they ripen and dry out, the seeds come adrift from their moorings inside and make a musical rattling sound when bumped or shaken.

There are two subspecies. The subspecies mitchellii (shown above) is more common on sandstone than on our basalt soils, though it does grow on red basalt ridges where the soil is light and well-drained.
The subspecies laevis has leaves no wider than 1.5cm, and grows only in the inland. It is a drought hardier plant, and more tolerant of heavier soils. Both subspecies can be found in our district.

Like many species of Crotalaria, they have been suspected of poisoning cattle, pigs, and horses. Feeding tests, however, show that the different species of Crotalaria vary widely in their toxicity levels. Tests with this one have failed to produce any signs of harm, so I feel we can grow them with a clear conscience.

Butterflies like this one - pretty little things with blue on their upper wings - take a great interest in our rattlepods. We suspect them of being a butterfly called forget-me-not (Catochrysops panormus platissa) - but are not great at butterfly ID! Can anyone help?

Friday, January 15, 2010

Cressida Butterfly Vine

Aristolochia meridionalis (Aristolochia sp D’Aguilar Range)
I was delighted to find this tiny plant at a friend’s place in Blackbutt, yesterday. We almost missed it, thinking it was a bellvine Ipomoea plebeia, but a sharp-eyed member of the company pointed out its tiny flower - definitely an Aristolochia!
There were several of the plants there, and we dug this one up, finding that it had a substantial fleshy root. That’s the secret of its this little vine’s ability to survive droughts, fires, and perhaps gardeners who attempt to weed it out, mistaking it for bellvine.
It is normally regarded as deciduous, which in the case of small vines like this one can mean not just loss of leaves every winter, but the loss of everything above ground. That it should have flowered while the plant seems so small probably means that it is really quite an old plant.
Like its cousin the Richmond birdwing butterfly vine, this is an important butterfly host plant, needed by the beautiful clearwing butterfly (Cressida cressida). Each little cressida vine can only host two or three caterpillars, so lots of them are needed to support a good population of clearwings.
I took the plant to an SGAP meeting last night, and a member commented on the resemblance of the flower to those of some of the carnivorous plants - and he is actually right that this flower is a trap.
The flowers catch a little midge, which they need as a pollinator - but aren’t seriously sinister. They have two stages - a female stage, when they are able to be pollinated, followed by a male stage, when their pollen ripens. In the first stage they are open for visitors, and exude a smell resembling a female midge pheromone. The gullible little males crawl deep into the flower’s long tube, in the hope of finding a mate. The flower traps them there, and keeps them until its pollen is ripe, only then releasing them with their new pollen load.
They’re not smart, these little midges. They go on to visit the next interesting-smelling flower, and get themselves trapped all over again.
The midges live in damp leaf litter and are said also to like being amongst the leaves of matrushes, Lomandra species - so successful reproduction of pipe vines depends on having the right environment for midges, as well as for their own growth.

Pipevines and the
Doctrine of Signatures

This is an ancient doctrine, but it still influences some modern herbalists. It holds that the appearance of certain plants is a divinely bestowed sign, put there to tell us that the plant is suitable medicine for the human body part it resembles. Kidney-shaped leaves mean kidney medicine, and so on.
The flowers of various species of Aristolochia and Pararistolochia are variously said to resemble a foetus in delivery position, an afterbirth - or a snake. Traditional medicine regarded them as valuable for easing childbirth, inducing abortions, reducing menstrual pain, and curing snakebite. These uses were surprisingly widespread, being practised wherever the different species grew - Europe, Asia, North and South America, and Australia.
Few people nowadays would regard a plant’s “signature” as a reliable guide to its medicinal reliability, yet one suspects that the Aristolochias' use in such widely separated cultures could indicate that they were actually effective to some degree.
However, like many medicinal plants, they should not be experimented with at home, as they are very poisonous. Unwanted effects include destruction of the kidneys, and death. (Another traditional use for one Aristolochia species is as an arrow poison.)

But I think you can see why I got so much pleasure, yesterday, from the discovery of this tiny plant!

Thursday, January 14, 2010


Parsonsia eucalyptophylla

Climbers are rainforest plants, really.

When our local climate really behaves as badly as it can- by which I mean that it gives us many years of tedious drought - there are not too many climbers that will tolerate it. This one does, though. A descendant of rainforest ancestors, it has adapted so well to life west of the Great Dividing Range, that it can be relied on in the toughest, most exposed positions. It takes drought, frost, and searing sunshine in its stride.

Gargaloos are a common sight in some of our ex-scrub areas, growing on fence-posts and isolated trees.

This roadside specimen was gloriously in flower last weekend. No prizes for guessing what its pollinating insects must be!
The flowers have a strong sweet perfume, which some people love, though it reminds me a little too much of rotting fruit. They can’t be relied upon to flower with this much enthusiasm every year, but do it very well when the rain comes at the right time.

This is a plant which could be used in gardens. It grows very densely, making a good job of disguising old tree stumps, and would do well on a sturdy trellis or pergola. We tend to think of it as a plant of the blacksoil, but it grows well also on the red.
(See the Article on Irongate Reserve, June 13 2008, for more photos of gargaloo plants, including one of a lovely trunk of a very old plant.)

Monkey Rope in Flower
Parsonsia straminea

This relative of gargaloo rarely flowers with this kind of vigour, so I was delighted to find it on this front fence at Blackbutt last weekend.

As you see, it is attracting beetles with even more success that its country cousin. Its flowers are as strongly perfumed as those of the gargaloo, but the fragrance is a little different - more musty.
I wondered whether special garden care was responsible for this glorious show of flowers, but apparently not. It was not planted by the homeowners, but found its own way there, and has never received a jot of special attention.
(For more on the monkey rope vine, see article, Aug 2009)

Thursday, January 7, 2010

Orange Mistletoe

Dendrophthöe glabrescens
This common mistletoe, with its unmistakable, skyward-curving flowers, is flowering on roadside gums west of Toowoomba at the moment. It is a plant of the inland, usually found west of the Great Dividing Range.
We rarely see this mistletoe on anything other than eucalypts, with mountain coolibah Eucalyptus orgadophila, being a favourite host. However, it does sometimes pop up on on some dry rainforest species (e.g. Acmena and Litsea species) and even on some introduced plants.

It is a showy mistletoe, and one which would be attractive as a garden plant, with its bright orange flowers that light up the host tree, and carpet the ground beneath.

Like the Amyema species, Dendrophthöe glabrescens is a host plant for Jezabel and Azure butterflies.

The mistletoes which we notice most often on gums are Amyema species. They attach themselves to a small branch, developing a conspicuous “join” (called a haustorium).

Haustorium, Amyema miquellii.

Dendrophthöe species don’t do this. Instead, they send a network of root-like runners snaking along and around their supporting branches, and plugging in at a number of points. The branch which supports them is not killed in the process.