Silver Croton

Croton insularis
Around the district, the crotons are in flower.
The flowers are interesting (to butterflies, as well as to us), but not actually particularly showy. With these plants, it is the scatter of bright orange leaves which are the main attraction. Every leaf turns bright orange before it dies, but unlike deciduous trees which use up all their glory in less than a month, crotons ration the display so it lasts all year.
New leaves are pale silver-brown, and the adult leaves all have silver backs, which show every time the trees is ruffled by the breeze. The bark is pale, too, so the overall effect is of a light-coloured tree.
These are very fast-growing small trees, suitable for the suburbs, and very useful for new gardens. When young they like a semi-shaded position and shelter from frosts.
They are equally happy in heavy blacksoil and our very lightest redsoil.
Though usually grown as single-trunked specimens, they can be pruned as a hedge, or coppiced (cut back to the ground) when they respond by producing multiple stems and re-growing as shrubs.

More Prickly Lixy

Alyxia ruscifolia.



Since my post of last month, these plants have only become more wonderful. They always flower quite well, but this year they’re outstanding. At Gowrie Junction today my companions and I were finding the plants by following the perfume as it wafted downwind. It resembles jasmine.





The shrubs were a mass of flowers, with the orange fruits still hanging on, and this lovely plant had a good crop of lichen on it as well - a sign of a healthy environment.


(Don’t, of course, believe the rumour that lichens damage plants. They do nothing of the sort, and are so interesting and varied in themselves that their richness only adds another dimension to a garden.)
I was interested in the comment by reader Mick last month that he has some prickly lixy with black fruit, down Ipswich way. That’s a variant I haven’t heard of before.

Hoop Pine Babies

Araucaria cunninghamii
Hoop pines can have thousands of these babies, scattered under the trees, looking like little green dragonflies. (Double click for s closer look.) There is a great crop of them in the Boyce garden at present.
They won’t grow, these seedlings, because the roots of the parent trees exude a substance which eventually kills them off. Biochemical inhibition, it’s called.
Flindersia species (such as crows ash, Flindersia australis) can do the same thing to hoop pine seedlings. Crows ashes like to be the tallest trees in their own neighbourhood, and can prevent themselves from being shaded out by any too-close hoops. So, unfortunately, can those feral pines which escape from our forestry plantings or from private gardens. In this case, however, it is the introduced pines which are the aggressive colonists, preventing hoop pines from reproducing in what was once their own territory.
Allan Cunningham, after whom the trees are named, never did get to the site where Toowoomba now stands - but he saw it from a distant vantage point somewhere near Grantham, long before any white person reached it . He was quite excited to see his newly discovered Araucaria dominating the skyline. It must have looked something like this view at Canungra.

The Boyce Garden (corner of Range and Mackenzie Streets, Toowoomba) is the last tiny remnant of the rainforest he saw, and even its hoop pines were planted in the 20th century. It’s amazing how thoroughly we ex-Europeans have managed to exterminate whole environments, since our ancestors first settled in Australia.

Palm-lilies

Cordyline petiolaris
These plants are fruiting prettily out at the Bunya Mountains at the moment.
Despite their common name, they are neither lilies nor palms. They are in the agave family, and are closely related to the imported Dracaena plants which are so popular in gardens. The locals are much more environmentally friendly, of course.
They are wonderful in a shady garden for a cool green effect. They grow quite fast fast to about 2 metres in height, then, slowing down, can get as high as 7 metres (though this great height is fairly unusual, and the result of growing in low light and needing to stretch to get their fair share).
In spring they have generous panicles of lavender flowers, which are followed by these red berries.
Like so many of our local plants of the dry rainforests, they cope well with drought - but do look their best, and grow faster if given water and a bit of fertiliser
In the wild they grow under trees, and do well in a similar situation in a garden. Being narrow plants they are also very appropriately fitted into the narrow strip between suburban houses, particularly in situations where there’s not a lot of sunlight. They are effective in courtyards, or as indoor plants, sculptural lines looking particularly good with modern architecture.

Hairy Boonaree

Alectryon pubescens
I was rather pleased with this hairy boonaree fruit which I found on a little tree in Franke Scrub, Cawdor, yesterday. They don’t fruit often, so it was good to be able to see its velvety capsule - the thing which distinguishes it from the very similar common scrub boonaree, A. diversifolius (see February 08)
The hairy boonaree is at the southernmost edge of its range, on the Darling Downs, and is not very common here.
Both these boonarees have very variable leaves, and similar showy “rooster’s eye” fruits. The leaves (and fruits) of A. pubescens are larger, but it can be difficult to be sure which of the two plants you’re looking at, as there’s considerable overlap.
Like all the Alectryons they have these bright red "cockscomb" arils, which swell when the fruit is ripe, bursting the seed capsules in half, and throwing off the little "cap". The beedy little rooster's eye seeds are almost completely surrounded by the aril, whose bright colour attracts the birds which eat the seeds and then "distribute" them to grow away from the parent tree.

This magnificent leaf was unusual even on the tree where I found it last year, on Mt Kynoch. I didn’t confirm the ID at the time, but it is probably another specimen of A. pubescens.

Rock Felt Ferns

Pyrrhosia rupestris
We often see these little ferns growing on rocks and trees in the rainforests. Sometimes people mistake them for orchids, but here is one growing out at Gowrie Junction which clearly shows that it is a fern. It has these little brown spore- patches on the back of its fertile leaves (or “fronds”).
All ferns have two kinds of leaves, the infertile ones having no spore bodies. In many species of fern, the fertile fronds are a different shape from the infertile ones. Sometime the difference is hardly noticeable - they are just a bit longer and thinner. In the case of these little ferns, they are so different from the little round infertile leaves that they could be mistaken for the leaves of a different species of plant.
They are interesting, botanically, in another way, too. Green plants create their own food by photosynthesis. Using sun-power, they convert water and carbon dioxide into body mass. This means that they absorb carbon dioxide through their pores (“stomata”) whenever there’s enough light for the process.
Pyrrosia ferns are unusual in that they can absorb carbon dioxide at night and save it up for the daytime. They can therefore leave their stomata closed in the heat of the day to prevent themselves from losing water - a knacky trick which is the secret of their drought hardiness.
Rock felt ferns are quite easy to establish on trees in our own gardens. The best way to do it is to choose a tree with permanent bark, then wait for a light shower of rain, one which will partially wet the tree trunks without saturating everything. Examine your target tree, and note where the flow patterns of the water make wet patches. Choose a wet spot which faces east or south, so the little fern won’t have to cope with too much sun of drying wind, and attach the fern there.
Meanwhile, keep an eye out for spore bodies on the backs of the fronds of all kinds of ferns. There are a lot of them about at this time of year, and they are an easily overlooked delight, each species of fern having its own characteristic pattern.

Black Plum-Ebony in Boyce Gardens

Diospyros australis
This morning, to my delight, I found this little ebony tree in Toowoomba City’s only remnant patch of rainforest. Friends and I searched for it without success last year, and were disappointed not to find it, as it is one of the important indicator species of that particular type of rainforest.
It is not so very difficult to identify, because of its dark green leaves which are strongly “two-ranked”, (in two flat, parallel rows), on branchlets which tend to zig-zag. Today, however, any doubts about identification would have been dispelled by the ripe black fruits, in their little cup-like calyxes which are typical of the ebony family. This was a female plant, of course. I didn’t find any males about, but there must be some there as this female was able to set fruit.
Plum ebonies are one of our five local species of true ebony, all of which are related to the Indian tree (Diospyros ebenum) which produces the famous, hard, black timber traditionally used for piano keys. Another well-known ebony is the persimmon (Diospyros khaki).
Our ebonies also have beautiful heartwood, and edible fruits.
I haven’t actually tried eating them, as I don’t expect to like them much. They are probably astringent unless very ripe, and might not ripen unless stored and picked. If you really want to try one, do make sure you don’t waste the seed. There are not enough of these trees around Toowoomba, despite it being the plant’s original habitat.
As with most rainforest seeds, this one probably loses its viability quickly. The trick is to not let it dry out. If you can’t plant it at once, keep it in a plastic bag until you can.
Plum ebonies can be grown as small trees, and like to spend their early lives in a shady place, but can eventually emerge, growing in the sun where their shady canopies are appreciated. They would also make a lovely hedge, in a shady spot. Their dense canopies make them favourite bird-nesting sites, and fruit pigeons love the fruit.
These are drought resistant, frost hardy plants, also suitable for fire-retardant planting