Thursday, December 29, 2011

Fire Pea

Tephrosia bidwillii
Family: FABACEAE



We have very few local plants with bright orange flowers.













This pretty little fellow was flowering last week.











It's a herb which grows among grasses in open woodlands on our local black soils, (often on hillsides), as well as on sandstone soils.













The plant looks as though it might have potential in gardens. So far as I know, no attempt has been made to cultivate it, so little is known of its growth habit.
Has anyone out there grown it? I'd like to hear from you!

Kangaroo Apple

Solanum aviculare
FAMILY: SOLANACEAE
These pretty plants are flowering and fruiting around the district now. They are familiar in our local national parks, where they grow on red soil, and on hillside black soil. It is seen at left in the Bunya Mountains...










...and at right in Goomburra National Park.




For several months in spring and early summer, it produces generous quantities of these attractive flowers.

Gardeners who grow potatoes, tomatoes, eggplants or chillies will be able to see, from the flowers, that this is a related plant.

Like those familiar food plants, the leaves and unripe fruits of kangaroo apple are poisonous. It is farmed in several countries of the world, to produce a drug, used in the manufacture of oral contraceptives, which is extracted from the young leaves and green fruits.

Solanum aviculare is native in New Zealand as well, and Maoris (who call it poroporo) cultivate it for the edible fruit. It should only be eaten when it is very ripe.



Aborigines traditionally burned off the outer skins, before they ate them.
This plant has potential as a garden ornamental. It is a fast-growing shrub, with large plants reaching 3m high, and is unlikely to live for much longer than five years. The leaves of young plants have large lobes on them, which disappear as the plants mature. It is useful as an ornamental filler in gardens, positioned between slower-growing, long-lived plants. It is also used as a rootstock for grafting eggplant.
New plants are easily grown from seed or cuttings
Kangaroo apple is moderately drought and frost hardy. It needs a sheltered site, and grows in full or part sun.

Thursday, December 15, 2011

Cheese Tree

Glochidion ferdinandi
FAMILY: PHYLLANTHACEAE
This tree was named for its little seed capsules, which grow on the female trees and once reminded some imaginative person of a wheel of cheese.



This may have seemed a reasonable analogy when you might have expected a cheese to be wrapped in cloth, tied up with string and dipped in red wax. Nowadays, we’re more likely to think they look like little pumpkins.
These on my neighbour’s tree are not ripe yet. As they mature, outer covering will (theoretically) peel off from the base, leaving a cluster of seeds which are covered by juicy red arils, on the tree. Red arils are always a sign that a tree is prepared to feed the birds, in the hope that they will spread the seeds about, so this is a good tree for a wildlife garden. I practice, I haven’t seen ripe seeds on my neighbour’s tree, so it may be suffering from the lack of a male partner to fertilise the flowers.
Dried immature fruits are added to pot pourri for an ornamental touch - but it seems a pity to pick them when they’re so pretty on the tree.


When it’s not fruiting, the tree can be recognised by its very shiny “two ranked” leaves. (This means that the leaves are arranged in two rows, and the branchlet would lie flat if you put it on a flat surface.)



This is only marginally a species of our district. It’s not found on the Darling Downs, but grows on the eastern escarpment near Toowoomba, and at Ravensbourne, in creeklines.


This well-shaped tree is about thirty years old. It was planted (in red soil) in what was a rather open space at the time, and survived many frosts before the other sheltering trees made frost less common around it. It had no supplementary watering from infancy, though there were good rains in its first few years of life. It has since thrived all through our long drought.



Cheese trees also grow happily under other trees - a useful garden characteristic - and would be an excellent tree to replace the privets which still choke many of our escarpment's sheltered valleys.
The species is a good orchid host.

Thursday, December 8, 2011

Kangaroo Grass

Themeda triandra
Family: POACEAE

The distinctive heads of this unmistakable plant are highly visible around the district at the moment, as they begin to go through their summer colour-change. The leaves go from light green to red-brown and the pretty flowerheads ripen to a showy russet-colour.

This was once Australia’s most widespread grass, and it is one of the easiest native grasses to identify.




Deservedly our most popular ornamental grass for landscape gardening, it is also useful in floral arrangements. One of the staples of a good wildlife garden, it is very attractive to birds, which appreciate the feast of large seeds. A nutritious plant, it is popular with kangaroos and wallabies, and with introduced livestock, which have grazed it heavily since the time of European settlement. Unfortunately it is easily killed by overgrazing, so tends to vanish from pastures.
It has been used in native lawn mixes, but just as it doesn’t tolerate heavy grazing, it can be killed by being mown too frequently or too short. It grows as a tussock, rather than spreading as do the better-known introduced lawn grasses, so you would only use it for a “lawn” in an area where this might be rather roughly defined!







"Cultivated grassland" would be a better term, and it would be a pity not to let it go to seed each summer.







In pre-European times, kangaroo grass was managed with a regime of annual (winter) burning, which refreshed the plants ready for the new season. Burning is hardly practical in a garden, but a cut-back after the seeds have dropped, by hand or a high-set lawnmower, will result in more vigorous plants as well as natural regeneration. It is better if the grass cuttings are collected and removed, as this is not a plant that likes mulch.
Collecting seeds for propagation purposes can be a little tricky, as they must be very ripe - firm and hard rather than milky, and there is only a narrow window of seed-collecting time before they fall off the plants. A successful technique is to put a seed-trap under the plant to collect fallen seed, and empty it daily until enough has been collected. The seed then needs to be stored for nine months for “after-ripening” before being planted. It needs a cold period to help it germinate, so seed which is taken indoors should spend 4 weeks in the fridge, before being planted out. It is time to plant it once the daytime temperatures are over 25°.
We think of kangaroo grass as the quintessentially Australian grass, so it’s a bit of a surprise to discover that it is also native to South Africa. There they call it rooigrass - an Afrikaans word meaning “redgrass”. It is the only African species of Themeda, and it was given its botanical name there. "Themed” is an Arabic word referring to a depression where water lies after rain and dries up in summer - a clue as to how the grass likes to grow - plenty of water to get started, after which it will happily tolerate drought. It’s also frost hardy.

Thursday, December 1, 2011

Native Caper Tree

Capparis arborea
FAMILY: CAPPARACEAE


Franke Scrub at Highfields is a mass of butterflies at present, and this tree is one of the reasons. It’s a native caper, one of our five local Capparis species, and is host to at least four species of local butterfly.







This rather conspicuous plant is on the edge of the scrub. To find it, just drive around the edge and look for the butterfly-like white flowers and the butterflies that are hovering around it.







It’s worth looking for it in the morning, when the perfume of the fragile flowers is at its best. They only last a day, losing their petals by early afternoon.





This magnificent little tree may be several hundred years old, and is a good example of the naturally small dry rainforest trees which are so suitable for suburban gardens. Alas, they are sometimes undervalued - people who will see a large tree as old and therefore worth preserving may clear small ones because they don't appreciate that they, too are living relics of the pre-European era, so have heritage as well as environmental value.
This specimen's age is the reason that it is difficult to find the spines which are the most obvious identifying characteristic of caper species. They grow in pairs at the base of each new leaf, on all but the oldest trees. In seedlings, the spines are long and straight, but as the trees mature, they produce short, curved ones. Young trees might still have the remnant paired spines on their trunks, but older trees lose the prickly habit. Spines like this evolved as part of the "arms race" with herbivores. They protect the plants, which are otherwise very tasty, from being eaten, when it is young. Taller plants with sturdy trunks are not so vulnerable, so don't need the spines.
For more about this and other local Caper species, see articles posted November 2009, and December 2008.

Mapoon Bush

Psychotria loniceroides
FAMILY: RUBIACEAE



This plant is flowering beside the walking track at Ravensbourne. The starry white flowers will be followed by yellow fruits which are edible when very ripe, but are rather insipid in flavour. The birds like them, though.





The name “loniceroides” suggests that the soft, velvety leaves are like Lonica - honeysuckle - but you’d have to say that the resemblance is slight!


In nature it grows as an understorey plant in dry rainforests. In a garden, it grows as a shrub, usually about 2m high. It is suitable for growing under trees and in densely shady places where it may stretch to reach the light, reaching as much as 5m in height. For a compact shrub in those conditions it would need pruning to keep the shape neat and the foliage dense. In full sun it won’t grow so high, but the foliage will be denser, and it will flower and fruit more prolifically.
Mulch to keep the soil damp will also improve the appearance of this drought-hardy plant. It needs well-drained soil, and grows very well on our local red soil.

Thursday, November 24, 2011

Crows Foot

Erodium crinatum
FAMILY: GERANIACEAE


This is a plant which some people don’t like to grow in their gardens, as they consider it weedy. I introduced it deliberately to mine some years ago. I am very fond of the bright blue flowers.




The plant is an annual that pops up in spring, fills a space with it’s fresh green foliage and delicate little flowers, and then is finished, needing to be pulled out, usually by early November. I always leave a few to seed, and they come up in the following year without any need for assistance. They are never very numerous, so I can’t say that I have found them weedy at all. Perhaps it’s their short life-span which some people object to?


The name “crows foot” is a reference to the shape of the leaf, but as you can see, it’s a bit of a stretch of the imagination to think of crows walking around on things shaped like this.



It is a very suitable plant for a children’s garden, because of its fast growth, and interesting seedpods. Their “storks-bill” or “cranes-bill” shape is typical of members of the geranium, but the ones from this plant are some of the most bird-like. As children my brothers and I used to use them to play at giving “injections”.

Being soft, they don’t hurt at all, unlike the polio injections which were the bane of every schoolchild in those days.
These are drought and frost hardy plants, and they like to be in full sun. They are easy to pull out once finished.
Aborigines ate the roots (roasted) as well as the seeds.

Golden Paper Daisy

Xerochrysum bracteatum, (Helichrysum bracteatum), (Bracteantha bracteata)
FAMILY: ASTERACEAE
The cheerful, long-lasting golden flowers of this Australian icon are probably our best-known wildflowers. They are flowering madly in grasslands and road verges, all around our district, at present - and will go on doing so right through to autumn. They are easy to grow from seed, collected at this time of year and planted in March or April. Some plants will persist into a second year, but for garden purposes they are best grown as annuals.
Xerochrysums (by various names - the nursery trade hasn’t kept up with the botanists’ name changes) are sold in nurseries. These are cultivars, developed for the generous size of their flowers and shorter, more compact plants, and are usually perennial. There are also some multi-coloured annual forms, easily available in punnets (with names like “Bright Bikini”). They are the result of breeding done in Germany in the early 19th century, where they were crossed with African relatives of the Australian plant.




Our local natives, however, are easy to establish in our local gardens, and are bright and pretty.





Cutting flowers for use in vases only prompts the plants to produce more of them. It is a particularly good practice early in the season, as pruning the young plants makes them bushier. They have a tendency to get leggy in late summer. Planting them together with low-growing plants, produces an attractive result.
Paper daisies make very good cut flowers. Put fresh into vases, they last well over a week even in air conditioning. They are also suitable for drying, either by being wired as soon as they are cut, or by being hung upside down by their stalks, which will dry stiff and straight. Newly-opened young flowers are the best for floristry of all kinds.
Like all daisies, this species attracts butterflies to gardens. The adults of all kinds come for their nectar, and the painted lady butterfly (Vanessa kershawi) can breed on them.

Thursday, November 17, 2011

Oakey Bottlebrush

Melaleuca quercina
(Callistemon quercinus)
FAMILY: MYRTACEAE

I am so pleased to have been sent information about a Callistemon species which I had understood to be still unnamed. (see my article Feb 2011).




Apparently this very local plant was given a name in 2009 by Lyn Craven, working for CSIRO at the Australian National Herbarium. He has at last sorted out a number of closely related plants, establishing that this one, which is only known to occur in the blacksoil country from Oakey creek to Clifton, is a separate species. It was described and named from a specimen collected in 1991 on the western side of Brookvale Park Road, 10k west of Oakey, by Betty Ballingall.
Its new name, "Melaleuca quercina" requires a little explanation.
The plants that so many of us know as Callistemons have been moved into the Melaleuca genus which explains the first part of its name. All the "callistemons" are now officially melaleucas.
The second part, “quercina” is a rather dry little botany joke. Quercus is the Latin name for the trees we Australians call “English oaks”, and their relatives, so quercina refers to the plant’s habitat. Oakey Creek's name really has nothing to do with oaks of the Quercus kind, which is part of the joke, of course. It, and the town of Oakey which stands on its banks, got their name from the river she-oaks Casuarina cunninghamiana which once lined the creek.
If you want to be politically correct you can spell them “she-oke”, which is the modern approved spelling. The people who gave them the name in the first place didn’t care about political correctness. They named them after the familiar English oaks because of a similarity between the timbers, both of which, when quarter-sawn, have prominent and decorative medullary rays. Adding “she” to “oak” was, I am sorry to say, the way those men expressed the perceived inferiority of Casuarina timber.
So the link between Melaleuca quercina and any actual Quercus is a very tenuous one indeed - but but I like it!
I suggest that, for a common name, we could settle for calling it "Oakey bottlebrush".

Thursday, November 10, 2011

Tall Lobelia

Lobelia gibbosa
FAMILY: CAMPANULACEAE
Here’s a little annual which I found flowering in the Pechey area last week.

It is sometimes known as “false orchid”, and perhaps it does look a little bit like a ground orchid - though orchid enthusiasts would disagree!

It’s a tall slender plant, often with just one stem. The narrow leaves on the lower part of the stem wither once it starts to flower. As you can see, its bright blue, one-sided flower spike makes it a showy plant for its size, which is about 40cm tall. However you would need a group of them for a garden display.
These lobelias can be grown from seed, and could be sold in punnets as native bedding annuals.
They like to be grown in well-drained soil, in part shade, and are frost resistant.
This one was growing naturally in woodland, with no more watering than the rain we get. However, in the garden, these plants do best if they are watered occasionally.

Saturday, November 5, 2011

Peacehaven Blog

Here's a new blogsite that you shouldn't miss!
http://friendsofpeacehaven.blogspot.com
As you can see, new botanic garden at Peacehaven is gettin up off the ground, and well worth a visit.

Thursday, November 3, 2011

Bush Butterflies

Velleia paradoxa
FAMILY: GOODENIACEAE
“Bush butterflies” is the name given to this pretty plant in Tasmania, no doubt because of the way it holds up its scented yellow flowers, so they seem to flutter above the plant.


Here, it goes by the more prosaic name of “spur velleia”.
It takes some rather close observation to find the spur after which it is named. It’s a tiny point which hangs down from the back of the flower.


I couldn’t manage to photograph it, so decided to show you the spur of a nasturtium instead. You certainly can’t miss this one! When you find a Velleia flower, check it out and you’ll find that it, too has a spur, albeit a tiny one.




To explain the spurs: You all know how seed-making works. Pollen from the male bit of a flower has to get onto the female bit of another flower. There are lots of variations on the theme of how it’s done, but a common one is for the flower to attract an insect to do the job.


It advertises with perfume and bright-coloured petals, carefully designed to direct the insect towards the centre of the flower while providing somewhere for it to stand. This aligns the insect in the desired position.

The insect is rewarded with a drink of high-kilojoule nectar, secreted by the flower from glands called “nectaries”, and in the process gets dusted with pollen, some of which brushes off on the next flower.
From a plant’s point of view, an insect which manages to get the nectar without doing the pollen transfer is a cheat and a fraud - but it happens. So flowers select their insects by providing facilities to suit those of the right size, shape, and behaviour.
One of these facilities may be a nectary spur. Insects which don’t have a long enough proboscis can’t reach down inside it to drink the nectar, so the supplies are kept safe until the right kind of insect comes along.
I’m not sure why this Velleia species was singled out to be named for its little spur, though, as a nectary spur is a common feature among the various Velleia species as well as the very similar-looking Goodenias.
Spur Velleia is potentially a good little garden plant. It is a short-lived perennial, fast-growing from seed, and producing a generous sprinkle of yellow flowers from early spring to autumn. It likes full sun, and just a bit of watering to get established. Once introduced to a suitable garden, it will self-seed each year.
This one of the Australian native plants that could easily be sold as a bedding annual, in punnets, for an instant spring garden.
Seed can be purchased from internet sources, or we can collect our own.

Telling the Goodenias from the Velleias.
There are a number of local species of Velleia and Goodenia, all with very similar-looking flowers. There are two ways to distinguish between them.
1. Velleias have a unique arrangement of the flower stem. Botanists, bless them, have a name for it - it’s called a “dichasium”. It means that the stem divides into three, with the centre stem having just a single flower, while the outer two stems each divide into three, with the centre stem having just one flower... and so on, according to the vigour of that particular flower stem. You can see it in the photo of Velleia paradoxa, above, but won’t find it on any Goodenias.
2. You’ll need to dismantle a flower to find the ovary. It’s the roundish bit that will turn into the seed capsule when it’s ripe (unless some curious person picks the flower, and dismantles it for science, first). In Velleia, the ovary is superior, in Goodenia it’s inferior. Superior doesn’t mean better! It just means that the ovary is above the point where the petals, sepals and stamens are attached. An “inferior” ovary is below that point. In some Goodenias, it is only “half-inferior”, while in others it’s clearly below the place where the petals are attached.

Friday, October 28, 2011

It’s Wildflower Time

Swainsona queenslandica
FAMILY: FABACEAE
I visited a most delightful property, last weekend, at Ramsay.
I always enjoy this time of the year when flowering herbs come into their own. In this case, the plant which made the property outstanding was the Darling pea, Swainsona queenslandica.


I am familiar with the species as a plant that is very common just west of Toowoomba, on the stony hillside black soil (sometimes called “chocolate soil”). It also introduced itself to my own garden on the red soil.
It gets mistaken for another Darling pea, Swainsona galegifolia, but can be distinguished by its wings, which are about the same length as the keel (unlike those of S. galegifolia which are only 60% of the keel’s length.)
It also has the habit of spreading by underground rhizomes, whereas S. galegifolia has a clump of semi-woody stems, all sprouting from a single crown.



My plants, and those west of Toowoomba, are bright, lipstick pink.
(See article Sep 2008)







Those I saw last weekend at Ramsay, south of Toowoomba, are orange-red. This photo shows the root structure, and the rhizome which connected this section of plant to another set of flowering stems.




They seem to be the perfect colour for accent plants in a bushland scene. I found I coveted them for use in shrubberies, to be seen from a distance, and felt very privileged to be allowed to take some of them home.
The interesting thing about the plants on this property was that in one case, they seemed to be suffering from an identity crisis, and were coming up pink. Clearly, the pink and the red forms are very closely related indeed.

Killing Typhoid Mary




I found myrtle rust in my garden yesterday.














We knew it was coming, of course, and I had been keeping a special eye on my brown malletwoods (Rhodamnia dumicola).




Although almost all members of the myrtle family (Myrtaceae) can potentially be affected by this nasty disease, I was aware that my malletwood is one of the most susceptible species, likely to be my “miners’ canary” for myrtle rust.
Having seen the new disease a few months ago in a nearby suburb (see posting on myrtle rust, July 2011) I had anticipated that it would probably arrive at my place, blown by spring winds, when the weather warmed up. So I was saddened but not surprised to find it infesting two little malletwoods on the eastern side (the upwind side) of our block. Only last week I posted new photos of them, in blooming good health. This week, hundreds of leaves were heavily infected!
A third plant in a somewhat more sheltered spot to the west of the block is (as yet) clean.
I rang Biosecurity Queensland and reported it. (They still want us to report new sightings at 13 25 23). Then I looked at the website which advises us on what to do with infected plants. http://www.dpi.qld.gov.au/4790_20154.htm
The site offers householders a choice of options ranging from taking no action at all, through the use of fungicides, to removing healthy plants as a preventative measure.
Because malletowoods are so very prone to myrtle rust infection, I decided that the plants should go, but cutting them out this morning has made me feel quite miserable!
I don’t plan to remove all infected species in the future, but in the case of these very susceptible plants I felt that attempts to save them by spraying with poisons would probably always be followed rather rapidly by reinfection. I just don’t want a heavily diseased plant in my garden - a continuous source of copious quantities of rust spores putting all my other Myrtaceae at risk (not to mention those of my neighbours, with whom I would rather be on good terms).
I went and contemplated the healthy malletwood, but couldn’t face the thought of removing it today after the emotional stress of cutting out the other two.
I probably should, though.

The Miners’ Canaries
There has been a lot of research done on myrtle rust since it was first found in Australia last year. There is a potential for it to infect almost all of the Australian species of Myrtaceae.
So far, over 100 species have been affected in the wild. There are likely to be many more plants which will suffer to a greater or lesser degree, and growers of Australian natives should become aware which of the plants in our gardens are members of the Myrtaceae family so we know where to look for the disease.
Scientific testing has been established that some species (such as the malletwoods) are very susceptible, some only moderately so, and a few species seem to be immune to it.
If we are looking for it in our gardens, the plants to check most regularly are the most susceptible ones. Some plants known to be badly affected are:
Willow Myrtle Agonis flexuosa (including cultivars “Afterdark”, “Burgundy” “Jedda’s Dream”)
Brown Myrtle Choricarpa leptopetala
Silky Myrtle Decaspermum humile
Beach Cherry Eugenia reinwardtiana
Thready-barked myrtle Gossia inophloia (with popular cultivars like “Blushing Beauty”)
Broad-leafed paperbark Melaleuca quinquenervia (our most familiar paperbark)
Malletwoods Rhodamnia sp. (also called scrub turpentines)
Native Guava Rhodomyrtus psidioides
Aniseed Myrtle Syzygium anisatum (Backhousia anisata)
Rose Apple Syzygium jambos (not native)
Water Gum Tristania neriifolia
Southern penda Xanthostemon oppositifolius
Sadly, these are likely to be plants which may become unpopular in home gardens, because of their higher susceptibility to the ugliness of myrtle rust.

Myrtle Rust Immunity
Early this year I decided not to plant any further Myrtaceae in my garden until more was known about myrtle rust. I had been hoping to hear that some of our locals might be found to be immune to it
The bad news is that the more it spreads, the more species are found to be susceptible.
The good(ish) news is that some plants, though they are infected, are not too badly damaged by it. Seedlings cop the worst dose, though, and we still don't know whether it will affect these species' ability to have babies.
The best news is that 11 species have so far been found to be immune. It’s not many, compared with the plants that have succumbed, but it’s better than none!
They include three locals - Brush box, Lophostemon confertus, Swamp Box Lophostemon suaveolens, and Gum-topped box, Eucalyptus moluccana.
Those of us who have been avoiding planting any new Myrtaceae can now go ahead with these species, happy in the knowledge that they are likely to continue in good health.
In the case of the gum-topped box, the koalas will be pleased, too.

Thursday, October 20, 2011

Brown Malletwood

Rhodamnia rubescens
FAMILY: MYRTACEAE




This small tree is flowering all around the district at present.





It’s a particularly pretty plant, flowering profusely from a very early age. (This plant is only three years old.)
In a month’s time it will be covered in small, red bird-attracting fruits.
See Jan 2011 for photos of the plant and berries.

Common Woodruff

Asperula conferta
FAMILY: RUBIACEAE
This is a modest little plant which can be introduced to a garden and let loose to make itself at home. It spreads by rhizomes, popping up stems where it will, yet is not dominant enough to crowd out other flowers. The dense, bright green foliage of tiny shiny leaves and the sparkling little white flowers make an attractive foil for flowers of other colours, filling what traditional gardeners might think of as the “Sweet Alice” niche.





It persists among grasses, so would be good in a native grassland patch. It is also suitable for garden edging, or among rocks or shrubs.









It gets straggly in autumn, when it can be cut back to ground level ready for the next season’s growth. This ability to regrow from the rhizomes also enables it to survive bushfires, popping up, freshly renewed, when the danger is past.
This tough little plant is hardy to frosts and droughts, and grown is full sun or partial shade
While the life span of an individual plant is indefinite because if its spreading habit, it would be desirable to have plants of both sexes so that they can also spread by self-seeding.

Thursday, October 13, 2011

Climate Change on the Eastern Downs

For most of us, the big climate change question has moved past the bickering about whether it is or is not happening, and whether it’s really being caused by humans.
Now, the questions now are to what extent the people of the world (including us) will be able to keep the change itself within reasonable bounds, how those changes that we are unable to prevent will affect us, and how best to cope with those changes we cannot prevent.
There is general recognition that climate change is not something humans will ever be able to prevent completely.However, the that we can and should do something to reduce the speed and extent of the change is becoming more widespread. An increasing number of individuals are making the choice to live “greener”. Investment in “green” technologies is now widespread, and increasing. Insurance companies are deciding that gambling on "no change" is likely to cause them financial pain, and local governments in coastal areas are planning strategies for coping with sea level rise. The most recent evidence of the changing weight of opinion is shown by our federal government’s recent decision to pass the carbon bills, a move that would have seemed unthinkable only a few years ago.

I recently got hold of the Queensland Government’s 2010 document on the subject, and found it interesting to read their projections (based on climate modelling done by the CSIRO) on how climate change is predicted to affect our own district.
In a nutshell, The Darling Downs will be hotter and dryer.
Calculations (based on the notion that the world will succeed in controlling its greenhouse gas emissions, to some degree), show that on the Eastern Darling Downs, average temperature is likely to be 1°C higher by 2030, average rainfall down by three per cent, and evaporation up by 3-4%. Of course these rather conservative figures will all be exceeded if there is no change (or less change than these researchers hope for), to the current rate of increase in greenhouse gases.
Whatever happens, we can expect fewer frosts, dryer winters, more heat waves and higher evaporation levels.
Water restrictions will be imposed more frequently. Those water conservation techniques that we learned, so that we could go on gardening during our recent 20-year drought, will be needed more than ever.
We’ll need to focus more on choosing heat and drought-hardy species for our gardens. We will enjoy our gardens more if we give up trying to nurse along those plants that would die if we failed to give then regular watering. As a trade-off, we may be able to grow some plants from northern districts which have previously been hard to keep alive through winter.
Australian native plants have had a long history of coping with climatic extremes, so are suitable plants to choose for a garden which will survive through change.
We are likely to show more interest in shady but drought-hardy trees such as our local dry rainforest species, rather than Eucalypts. (We love them, but they don’t keep the heat out of the garden.)
Scrub Wilga Geijera salicifolia( a dry rainforest species) and an Ironbark, Eucalyptus sp. both growing well despite the complete lack of garden care, both equally drought hardy. The wilga wins, in terms of providing livable shade!
Natural regeneration of native plants is likely to result in a slow move of our local species’ ranges, from north to south, and from west to east. Birds and other wildlife will change with the vegetation. Those native plants (some of them already very rare) which survive because they grow on cooler mountaintops may find themselves pushed uphill to extinction. Our conservation attempts should focus on these species.
Weeds which are currently kept in check by our frosts may invade. The effect will probably be greatest with woody plants and grasses. Highly flammable species like green panic, which loves to grow on rainforest edges, will increasingly threaten ecosystems that have previously been able to avoid being burnt because their plants have some ability to resist catching fire. (Once set alight, however, these plants are killed.)
Fires are likely to increase, putting pressure on those ecosystems such as rainforests and scrubs whose plants die when burned, and allowing them to be replaced by fire-tolerant species such as grasses and Eucalypts. Meanwhile, householders are likely to want to replace very flammable species (especially Eucalypts and introduced conifers) with non-deciduous plants that have green canopies and a reputation for not catching fire easily. Burning off, a practice which reduces short-term fire risk, but promotes an ecology dominated by flammable trees and grasses, is likely to come under review.
Plant diseases are also likely to spread southwards. So will diseases which affect humans, especially those borne by mosquitos. We may need to become much more careful, as tropical gardeners are now, not to risk our own health (as well as that of, for example, our neighbour’s children), by being careless about having water in the garden.
Our creeks and rivers will run dry more often, with a decline in both water quality and the native species that depend on them. The country is already addressing this problem by reducing rights to harvest water for agriculture. The decisions as to who has a right to how much water is fraught with difficulty, but I do hope that the needs of native plants and animals will continue to be factored in, and balanced with the very reasonable desire by landholders to make a living from their land.
Groundwater supplies will not be replenished at the current rate. We may see more use of soil surface treatments (such as mulch) designed to allow water to soak into the ground rather than run off. Driveways and other outdoor paving might also be used for water harvesting.
We can expect to see more restrictions placed on the use of underground water, as the levels drop ever more rapidly. It’s not wise to spend money on a bore in the belief that it will continue to be possible to fill gardens with plants from wetter climates, and keep them green with unlimited free sprinkling.
We will see more intense storms, rainfall events, and hail. We shouldn’t be lulled, by calculations of dubious mathematical integrity, into believing that last year’s “inland tsunami” was a “once in a hundred year event”, (or some such flaky figure). Our homes and gardens need to be designed to cope with such destructive summer downpours as the one in 2010. (So does all our public infrastructure, but that’s another story.) On the plus side, it is well worth putting in effective roof gutters and extra tanks to harvest these summer windfalls and save them for the increasingly dry winters.
Crows Ash Trees Flindersia australis. This Toowoomba residence takes advantage of a cool site among old trees.Built for Australia's variable climate, this is a dry rainforest species which is likely to weather climate change gracefully.

Friday, October 7, 2011

Hedge Saltbush

Rhagodia spinescens
FAMILY: CHENOPODIACEAE
We caught this cockatoo, the other day, picking pieces off our saltbushes, and flying away to comfortable perch to nibble at the leaves.
Saltbushes are some of the very best plants for a wildlife garden. Their leaves are so very edible by all kinds of animals, (even by humans), and the fruits are popular with small birds.
Hedge saltbush make a very dense ground cover to about 50cm high, if grown in full sun. It excludes weeds very effectively, as well as providing shelter for small creatures.

This saltbush species tends to spread, as the branches lie down and take root, a process which makes them useful for retaining banks.

In this case where they’re being allowed to creep up the slope. New plants are easy to make, and some blanket planting would have the bank covered in a shorter time.
As its name suggests, it also makes a good hedge, with a once-a year trim (in late autumn) needed to keep it to the desired width.


The blue-grey leaves are attractive year-round, but the plant is particularly pretty from February to autumn, when it is in fruit.

When used in landscaping, this plant sometimes pruned a little more than is really necessary and the pretty, bird-attracting fruits never appear! For a good show of fruits, it should be pruned once a year only, in early winter.
Notice the shape of the leaves. In southern forms of the plant the leaves tend to be hastate or triangular. Our local form, with its grey-green oval leaves is a good contrast plant where other saltbushes such as Einadia hastata or Rhagodia parabolica are grown.
See Feb 2010 for more on this versatile plant.

Monday, October 3, 2011

Mountain Burr Daisy

Calotis cuneata
FAMILY: ASTERACEAE

The season is having a hard time getting out of its winter jacket this year - but we know it’s really spring when the daisies start coming out again.
After a slow start, the flowers are beginning to be seen in our local greasslands again.
We have tended to ignore our local daisies for garden use, yet there are a number of suitable species - modest little plants with considerable charm. Several of them, The Calotis species, area mixed blessing because each seedhead matures into a little prickly ball of seeds, which can break apart on contact, and leave seeds sticking in your socks.

The one pictured here is called "mountain" daisy, but this seems to be a bit of a misnomer, as it grows on the gently sloping blacksoil hillsides west of Toowoomba.
This is really only likely to be a nuisance to those who tramp through patches of them, though. The prickles are really neither very sharp or particularly annoying.
Meanwhile, the fresh white daisies are plentifully produced over a long season, and could be a worthwhile addition to a garden. They grow easily from seed, and also spread (though not too vigorously) by underground stolons. They would be happy to be left to creep around in a mulched area of garden.


They are short-lived perennials, best replaced from seed every three or four years. They are quite likely to do this without any help from us, coming up as self-sown seedlings where conditions are right for them.
As with all our local daisies, they are very hardy to frost and drought, and will grow in full sunlight or dappled shade.

Friday, September 23, 2011

Black Bootlace Orchid

Erythrorchis cassythoides (Galeola cassythoides)
FAMILY: ORCHIDACEAE

It’s flowering time for this fascinating climbing orchid.

It’s a plant with no leaves at all, and is of the kind that is often called a “saprophyte”.



Most of the world’s plants need green stuff for survival. Chlorophyll is what makes leaves green. It’s a substance that is essential for photosynthesis, the process which is the plant equivalent of eating. Photosynthesis uses solar power to combine carbon (taken from carbon dioxide in the air) with hydrogen (from water, which is made of hydrogen and oxygen) to make carbohydrates.



Our bootlace orchid, however, has nothing green about it. Its rather evil-looking black bootlace stems come up from roots which are getting all the food the plant needs by being parasitic on certain soil fungi. The fungi, in turn, are growing on dead plant matter. The term “saprophyte” comes from sapro (decay) and phyte (plant). It means a plant that lives on decaying matter. Nowadays, however, the term is falling out of use, because it is now understood that the alleged saprophytes are really living on the soil fungi, which are themselves living on the decayed matter, Strictly speaking the plants are not saprophytes, but “myco-heterotrophs”!





Bootlace orchids climb up the trunks of their trees with these spongy, water-absorbing roots. For most of the year the plants are quite inconspicuous, but in spring they put out a great show of flowers.






They are closely related to a Mexican climbing orchid, Vanilla planifolia, the source of the vanilla we use for flavouring. You can see the bootlace orchid’s seed pod, which appears in February, does look rather like a vanilla pod.








Bootlace orchids are always found growing on eucalypts which are completely or partly dead - another good reason for not being too “tidy” about clearing away dead trees on our properties.