Thursday, May 29, 2008

Resurrection Ferns

The Only Truly Drought-hardy Ferns
Cheilanthes species
We are accustomed, in this district of drought-hardy plants, to those which look dead in dry times then revive when it rains. Some do it by letting their leaves die, and re-shooting from the stems. With others, it seems to be the whole plant that dies, but under the ground the roots, or perhaps the tubers, hibernate waiting for rain to wake them up. Still others put all their drought-hardiness into their seeds which will can remain viable, in some species, for hundreds of years.
This fern, however, has an amazing trick. Those very leaves which seemed quite dead - they were brown, dry, and crisp on their stems - can soak up a shower of rain and become soft and green again. Plants which were looking miserable only yesterday may be looking as good as new tomorrow, with this little bit of rain we've had.
Resurrection ferns are hardy in other ways as well. They cope happily with full sun or shade, survive frosts, re-grow from their roots after bushfires, and grow naturally in both acid and alkaline soils. Their only dislike is having their roots disturbed.
There are three local species.
The “mulga fern”, Cheilanthes sieberi, shown in the photograph above, is the tallest of them at 25cm. It differs from the others in being hairless, and in being the easiest to grow.
“Bristly cloak fern”, C. distans, has shiny black stems like those of the mulga fern, but the leaves are hairy on the undersides. It only reaches a height of 20cm, and may be the frost hardiest of the three. Unfortunately it can be difficult to grow and is very difficult to transplant successfully.
The “Woolly cloak fern” at left, (C. lasiophylla) is hairer still. Both the leaves and the stems are hairy, with the unfurled fronds, as you can see, looking, as the name suggests, rather white and woolly. It is the smallest of the set at 15cm.
All three are plants which, once established, are well worth having. Because of the difficulty in transplanting them, they should be valued where they occur naturally.

Friday, May 23, 2008

Corky Milk Vine

Secamone elliptica
The delicate tracery of fine branchlets and little leaves on this vine, together with its stunning corky trunk, make it a good potential garden subject. It is very drought hardy, and like to grow in full sun or dappled shade.
Corky milk vines grow in our local dry rainforests and vine scrubs, most often in sites where hoop pines also grow naturally. They have small, star-shaped, yellow flowers (pretty enough, but too small to be classed as decorative), and pointed, pencil-sized seed follicles produced in pairs at the end of hanging stems. These hold themselves horizontally - pointing, between them, at a quarter to three - and are quietly ornamental as they mature from green to brown, then split to let their seeds float away on their silky parachutes.
Mature plants have very attractive, thick, corky bark, with pronounced longitudinal furrows. The stem in the photo is 5 or 6cm in diameter.
They are host plants for the caterpillars of the beautiful blue tiger butterflies, one of the kinds of butterfly which deliberately feed on poisonous plants. Absorbed into their bodies, it defends them from birds.
Our native birds have learned not to eat them, of course, but some birds which have suffered from the milk vine’s poison are ostriches, which have died from eating the seed follicles. It is not likely to be a problem in a garden, but the slender stems do “bleed” white sap if broken. As with all milky-sapped plants, care should be taken not to get it in your eyes.

Thursday, May 15, 2008

Spear Lilies in Seed.

 Doryanthes palmeri
My neighbour’s spear lily flowered magnificently last November.

It's now producing loads of seed, so it's time to to collect ready for spring sowing, if you would like to grow this spectacular local plant.

Very adaptable plants whose only inflexible requirement is well-drained soil, they grow exposed to the west as with my neighbour’s plant, on very exposed (but damp) east-facing sites as we see at Cunningham’s Gap...

...or in dappled shade as in Goomburra national park.
The leaves of Doryanthes species produce high-quality fibre, so are a good choice for those who want to grow plants for basketry and other crafts.
There are a few of these native agaves growing around Toowoomba - though I find it a sad commentary on the state of native plant-growing that we see considerably more specimens here of its cousin the Gymea lily, Doryanthes excelsa. Gymea lilies are more popular in gardens not because they are better plants, but because species which grow naturally around Sydney are inevitably better-known and easier to buy in our nurseries than are our own natives.

Nardoo, an Australian Icon

Marsilea species
Marsileas occur around the world, but have a special place in both Aboriginal and white Australian culture. They were a very important food source for aborigines, before white settlement
They also have a place in our history books as the plant on which the explorers Burke and Wills allegedly starved to death. When they ran out of food, the hungry explorers were shown by aborigines that they could eat nardoo sporocarps. They may have also been shown how to prepare them, but the history books are silent on this point. Correct preparation involves soaking to leach out a substance called thiaminase, which destroys vitamin B1.
Wills’s last journal entry comments “starvation on nardoo is by no means very unpleasant, but for the weakness one feels, and the utter inability to move oneself, for as far as appetite is concerned, it gives me the greatest satisfaction”. These symptoms describe beri-beri, a disease caused by vitamin deficiency. Poor Wills was probably not starving at all.
Nardoo is actually a kind of fern, as you can see from examining new leaves. They unroll in classical fern-frond style. It’s unusual in having its spores in capsules arising from the stems, rather than the usual fern arrangement of fuzzy brown patches on the backs of the fronds.
I notice that pressed specimens of the silvery-leafed common nardoo, Marsilea drummondii, can be bought in newsagents labelled “lucky four-leaf clover”. They are a pretty ornament, but I question what sort of luck might be received by someone who tries to cheat in this way!
As water plants go, nardoos are remarkably drought resistant, especially in heavy clay soils. The hardiest of our three local species is Marsilea hirsuta. It has plain green leaves and is a plant of periodically flooded soils - only marginally a “water plant” at all. Next hardiest is the common nardoo M. drummondii, whose range extends from floodplains to water 30cm deep. In water, the leaves are plain green, but on dry land they are covered with fine silvery hairs - very pretty. Both these plants cope with drought by dying back to their underground roots, and waiting for the rains to give them a new lease on life. The sporocarps can survive in dry soil for at least 100 years!
The best nardoo for deeper ponds and dams is the one with patterned leaves, M. mutica (pictured above), which grows in water to 1m deep, (as well as wet soil).
Nardoos thrive in both acid and alkaline conditions, survive frosts, grow in full or part sun, can be kept in pots, and are generally a trouble-free plant for gardens.

Thursday, May 8, 2008

Those Useful Matrushes

Lomandra species
These tough, drought and frost-hardy clumping plants are usually grown for their foliage. They have great potential for contributing to a garden picture, with their strong lines and texture.
Some have interesting flowers as well, with male and female plants having somewhat different-looking ones.
They are related to grasstrees and have equally tough leaves, very suitable for mat-weaving and making bags and baskets, and, of course, mats.
Most of us are familiar with the long-leafed matrush, Lomandra longifolia, which is so widely used these days in landscaping. It grows to a 1metre x 1metre clump of long green leaves, and needs no attention at all once established.
Isolated clumps make great fillers between shrubs and trees, rows (planted 50cm apart) make good garden edges or soil-retaining contours on slopes. Whole areas can be planted, at a rate of 6 plants per square metre, to form a patch of dense, weed excluding greenery. Used in tubs, they look good in formal gardens.
The spiky cream flowerheads produce a good perfume for a short time - stronger if they’re planted in the shade - but are generally not an ornamental feature.
This is such a useful plant, that its cousins are often overlooked. There are four other local native Lomandras, all worth seeking out.

Crowded-leaf Lomandra
Lomandra confertifolia
This is a completely different-looking plant. Even people who are familiar with matrushes might mistake it for grass, when it’s not in flower. The soft-looking, dense clumps of very narrow leaves grow to about a foot high.
This is also a popular landscaping plant, which actually creates a problem for those who wish to grow local natives. It is a very variable plant, so plants with blue-green leaves, longer leaves, more flowers, and so on have been brought into cultivation from various parts of Australia are fairly easily available, while our local plant might be hard to source.
It’s a slow-growing plant, but a good one for a low-maintenance, weed-excluding ground cover or garden border, if planted at 30cm intervals.

Wattle-flowered Matrush
Lomandra filiformis
Perhaps the neatest of a rather neat-looking plant group, this is a very good plant for formal gardens. Its neatly rounded clumps of very shiny, yellow-green leaves grow somewhat less than knee-high, and make a strong statement for their size. The flowers look rather like wattle blossoms which have lost their way.

Delicate Matrush
Lomandra laxa
Slender tussock, 30cm
This is a rarely-grown plant of rainforest edges. People planting matrushes are generally looking for tough weed-excluders and soil retainers. This is neither, but is a graceful plant with a dainty and elegant spike of pretty white flowers, well worth a small place in a garden.

Multi-flowered Lomandra
Lomandra multiflora
This little plant has the prettiest flowers of all the lomandras with the possible exception of L. laxa. They are quaint, brown and cream things, produced in generous bunches on the slender tussocks. I was surprised to find these specimens in flower a few weeks ago, as I thought they would have finished for the year.
Matrushes are long-lived plants.
They are host plants to a number of native butterfly species, so are highly valued by those environmentally aware gardeners who like their plants to be more than just pretty faces.

Friday, May 2, 2008

Native Plumbago in Franke Scrub

Plumbago zeylanica
We were delighted, at our working bee on Wednesday, to find this plant still in flower. We first noticed it in January.
This pretty dry rainforest plant may once have been quite common in the Toowoomba area, but is now rare here in the wild. It is an international species, growing also in Asia (including Ceylon, as the name “zeylanica” implies). You often see it described as “white-flowered leadwort”, but the local variety is pretty shade of pale blue.
Plumbago plants are traditionally called leadworts, a name which comes from a traditional use of a European species. Beggars rubbed the sap on their skin to raise nasty-looking, lead-coloured blisters - sick-looking beggars were more successful at their trade!
The juice of our local species might produce similar results, though it seems to be no problem with ordinary garden handling. The children’s game of making dangling “earrings” - attaching the sticky flower-bases to their earlobes - does them no harm.
P. zeylanica is also native in Africa, where its juice was used in traditional tattooing. A root extract is still used as a medicine for a variety of diseases in Asia. (Overdoses are deadly, however.)
If grown in full sun, (as seen at Peacehaven Botanic Park at Highfields), this plant makes a very successful, dense, under-knee-height groundcover. It spreads by underground roots.

In a shady situation it grows more thinly, making a rather inconspicuous, light understorey plant. In a garden, it can be left to spread at will amongst shrubs, where it is hardly noticed until it produces its flowers. They are very similar to those of its introduced South African cousin, the common garden “cape” plumbago, P. auriculata (P. capensis), which a much larger plant - a scrambling, sprawling shrub popular for its flowers and its ability to survive without attention from a gardener. Not everyone loves it, though, as it spreads vigorously and can be a nuisance to you, as well as to your neighbours and the local bushland. It can be distinguished from the local plant by its little “ears” - (actually stipules) on the stems, just where the leaves join onto them. (See photo at right). Note that the leaves are also a different shape.
A native butterfly called the “plumbago blue” breeds only on these two plants. Butterflies of all kinds are attracted to sip nectar from the flowers.

Gumbi Gumbi

Pittosporum angustifolium (Pittosporum phillyraeoides)
Gumbi Gumbi are in fruit all around the district at present, and very pretty they look, too. Their profuse, creamy-yellow, butterfly attracting flowers appear from winter to summer. The sticky red seeds shown in the photo appeal to birds. King parrots feeding on them do make a lovely sight! There is a story that the seeds are so bitter that they ruin the flavour of the meat of emus which eat them.
This is one of our best local native plants for garden use. It’s a fast-growing (but long-lived), elegant tree, with slender weeping branches. Young plants tend to have an open growth habit - but as you can see from the photo of this roadside specimen, the canopies thicken up with age to form a dense screen or shady tree.
A well-watered specimen achieves this height and density in two or three years, and keeps its foliage right down to the ground for many years.
Gumbi gumbi are rewarding subjects for clipping. You often see lollipop-shaped “topiary” trees in paddocks, where pruning has been done by cattle or sheep. They would also be good hedging plants. They are able to flourish despite strong competition from other plants, such as overhead eucalypts.
These frost and drought hardy plants cope well with exposed sites and poor soils. They thrive on rocky or gravelly sites, and heavy cracking blacksoil - but really flourish on redsoil and good garden soils.
They are very easy to grow from seed, and like to be put into the ground while they are still very young, so their fast-growing roots can go deep without the “check” that they suffer if kept too long in a pot.
Gumbi gumbi roots do seek water. Planted specimens should be kept well away from drainage lines.