Sunday, April 29, 2012

Stiff Jasmine

Jasminum simplicifolium subsp. australiense  (Jasminum volubile, Jasminum australe)
This plant has been attracting attention around the district, over the last month or so. All through the long drought, it produced few fruits, but this year must have been just right for it. It is usually a rather inconspicuous climber, but it is being noticed for its generous bunches of fleshy black berries, with their dark red finger-staining juice.

The fruits are (theoretically) 2-lobed, consisting of two fruits with a single seed each. They are all conceived as twins, but many of the seeds are aborted at an early stage, so the fruits become singletons. Sometimes you tiny fleshy globe, indicating  where the second seed was aborted.
Unripe green fruits have a rather attractive pearly sheen.
Stiff jasmine is a hardy plant, growing in habitats ranging from wet rainforests where it is a large, woody-stemmed climber, to drought-prone vine scrubs where it grows as a bulky scrambler. It will even thrive in an open site where it has nothing to climb on, becoming a large, tangled, bird-sheltering shrub. It can even be pruned to make quite a neat hedge, though it doesn’t like to be confined too narrowly.
It could be grown on a sturdy pergola. A fast-growing plant, it would soon provide a shady green roof with bird-appeal.
We have four local species of native Jasmine. All have white flowers with the typical strong “jasmine” fragrance.

This species has the largest flowers (though in most years it doesn’t produce very many of them). As is typical of rather primitive plants, it can’t decide how may petals it should have, so you will see flowers with anything between five and eight of them.
This plant is closely related to the weedy introduced privet (Ligustrum lucidum and Ligustrum sinense), and seedlings of the two can be confused with each other.

Friday, April 20, 2012

Strychnine tree.

Strychnos psilosperma

This is a very pretty small to medium tree species, with a shady canopy of glossy green leaves and very attractive fruits at this time of year - but it’s probably not wise to grow one in a garden. A number of Strychnos species grow in Africa and Asia, and some of them are very poisonous. It is probably true of the seeds of all of them.

However the fruits of some strychnine species (in Egypt, Senegal, India, and Java)  are used as food. I do not know whether our Australian species has been tested for toxicity, so believe it is best to treat it with great caution.

Strychnine tree is sometimes accused of poisoning stock, but no evidence has been collected that it actually does so. This may be a case of an assumption being made on the basis of the plant’s name - or may indeed be a fact. It would be reasonable to leave it where it grows on grazing properties, so long as it is somewhere where the fruits are unlikely to be eaten by children.
It is sometimes cultivated, but on the whole, plants like this are dependant on conservation of the natural environment for their survival - another reason for making sure that patches of scrub on private land and in reserves are preserved from clearing wherever possible. Every plant species has its part to play in the ecology, and this one provides nectar for small insects in its perfumed flowers, and its seeds are eaten by birds.

A feature which can help us to recognise the tree are some little spines, which grow in the leaf axils.

In younger trees these are in conspicuous pairs. On this old tree there were very few spines to be found, so it was difficult to find any to photograph.

This tree grows in our local dry scrubs, where I’ve seen it on black soil slopes at Gowrie Junction.

Thursday, April 19, 2012

Crows Nest Fern

Asplenium australasicum

Oh, the difficulties of rainforest photography!
Despite the poor quality, I couldn’t resist sharing this picture Of a crows nest fern growing on an old vine. Nature’s artistry sometimes achieves a composition that not the best landscape gardener can match!
The photo was taken at O’Reilly’s, but this plant can also be found in the rainforests on the edge of the Darling Downs.

Growing naturally on rocks or trees in rainforests, or sometimes on the ground (if the drainage is good), these hardy ferns can grow to more than 3 metres in diameter - the size of a small bedroom! They depend for their nutrients on leaves and other debris which are caught by this saucer-shaped plant. They tumble towards its centre where they lie and decay, releasing their component parts for recycling. Garden specimens, especially those grown where the natural spatter of falling organic matter is scanty, appreciate a small amount of good compost or leafmould placed in their centres from time to time.

 New fronds form in the centre, usually unnoticed until they begin to unfurl, refreshing the plant with a new rosette of shiny green leaves.


Old leaves are best left on the plant, as they form a skirt which shelters the roots from drying out.

If you buy a crows nest fern from a nursery, you might be getting this species, or you might get the very similar Asplenium nidus from North Queensland. It is worth growing the local species, as it is much more tolerant of drought and cold. We can find out which one we have by examining the midribs of the frond. In A. australasicum they are flattish above and have a sharpish keel beneath. The midrib of A. nidus  is rounded above and beneath.
These two species, between them, may well be the most commonly grown fern type worldwide. They are often grown in a pot or stump or on the ground in well-drained, high-humus soil, where they have room to form their magnificent circular rosettes. Attaching them to trees results in a semi-circular plant. It is said that a circular, adult plant can be cut in half for attaching to a tree or slab. I haven’t tried this, so would be interested to hear from any readers who have done it successfully.
Depending on your natural rainfall, a well-established plant in a shady, sheltered position may be able to manage without supplementary watering. A little extra water is always appreciated, however.
This plant is also native to South-east Asia, where the young fronds are cooked as vegetables. The fronds make a wonderful, long-lasting addition to floral arrangements.

Brush Box

Lophostemon confertus
Logging is an essential industry. We all use timber products - and have been able to get them too cheap. If we had to replace all the trees we used in a lifetime it would cost us so much more than we really pay.

It has had some effects on our local vegetation, of course. Not only have many good timber trees been removed. Forest management has also resulted in the removal of old trees which are of no value to us, and were cleared to make way for healthy regrowth. The result is that it can take us by surprise to see old relatives of our familiar trees.
I recently had the change to visit the famous “Wishing Tree” at O’Reilly’s.

There must once have been Brush boxes of these proportions in our district, but I have never come across any of them.
 This hardy species is common along the Great Dividing Range. It belongs on the edges of rainforests, and if we see it growing naturally, we know something about the amount of rainfall that is received by that piece of land.
It is such a useful tree that it deserves to be more widely planted. It makes a beautiful specimen for parks and large gardens, and is used as a street tree in Toowoomba. It is too large for the average suburban garden, though, and shouldn’t be planted near underground drainage pipes.

It is the only non-eucalypt whose leaves are eaten by koalas. The flowers are a good nectar source for bees, producing a good pale honey, and its seeds are eaten by rosellas. And of course it has very good timber - hard, durable, and particularly suited for heavy construction and flooring.
Nurseries sell plants which produce red new leaves, but our local variant has bright yellow ones. (I once traipsed far across country to discover what that lovely "flowering" tree was.)

  In fact, the spring flowers are white with a lovely form. The name “lophostemon” means “crest-stamen”, and with a little imagination you can see the resemblance between its stamens, and the horsehair crest on the helmets of ancient Greek warriors.

Cutting down of brush box trees often results in coppice regrowth - a useful technique where a tree is too large for its site but a grove of smaller trees would be welcome. It’s also a way to produce a cut-and-come-again firewood tree, for those who like to get their winter warmth from a renewable resource.

Wednesday, April 4, 2012

Staff Vines - for the Birds

Celastrus subspicata
Our district contains a range of rainforest habitats, from the lush, wet gullies of the Bunya Mountains and Goomburra, to the drought hardy semi-evergreen vine thickets of our western slopes. Commonly used alternative names for their vegetation types are “vine forests”, and “vine scrubs”. Between them, they are home to about 80 species of climbing plant.

These local native vines are decidedly under-represented in our native gardens and rainforest plantings, which is a pity because of their very high value to our local wildlife.
Staff vines are particularly appealing to birds because they form dense thickets of sheltering foliage, full of safe nesting sites. Their distinctive stems, sometimes a strong orange colour, are liberally speckled with raised lenticels.

They are dioecious, so both male and female plants are needed to produce seeds. If grown from cuttings from a plant of known sex, this is no problem. Cuttings from a mature plant will also flower and seed at an earlier age than seedlings, but seedlings have the advantage of deeper roots which makes them drought hardier and likely to live longer. If planting seedlings, it's a good idea to put in at least five to be sure of getting at least one of each sex. They can be planted close together, which will create a good bird-sheltering thicket (or cover for a carport-sized pergola) quite quickly, even where the plants are still too young to flower and fruit.

They flower in November. Individually, the little greenish flowers don’t look like much, but a plant in full, fragrant flower can put on a lovely show.

Masses of tiny insects are attracted to the nectar feast, and in turn provide high protein food for nesting birds.

Female plants then set seed, producing little orange seeds capsules which split open like three-petalled flowers.

The fruits can can be found around the district at this time of year. Look for them in the scrub, where individual plants produce great quantities of seed over a long fruiting season, providing a second annual feast for birds.

Many local vines are restricted to damp rainforests, but staff vines are tough, drought-hardy plants which like to grow in a sunny position and can easily be grown in water-wise gardens. If they find nothing to climb on, they form dense tangled masses of shrubbery. They are large vines, but can be managed with pruning for smaller gardens.

This specimen has overwhelmed a small roadside tree, but larger clumps of trees happily co-exist with staff vines. In a garden we might prefer to grow them on a strong trellis or pergola, where they will form a shrubby screen or a shady roof. To produce the bird-attracting fruits it might be necessary to grow several plants, so as to have at least one plant of each sex.

This is such a desirable plant for a wildlife garden that it is worth establishing wherever room can be found for it.