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Short items of interest about Australian plants selected from the many newsletters and journals published by member Societies of ASGAP.......
Short Cuts in this issue:
- The Family Malvaceae
- A brief introduction to Australian members of the Hibiscus family
- When is a Plant a Weed.....
- ....and when is it a useful volunteer??
- Growing Sturt's Desert Pea
- This spectacular wildflower defeats many attempts at cultivation
- More Growing Sturt's Desert Pea
- If one method doesn't work....try something else!!
- Happiness is a Hibbertia
- Colourful plants to light up any garden!
- Basic Propagation from Seed
- It's not difficult - why not give it a try?!
The Family Malvaceae
Most people are familiar with the exotic Hibiscus but few possibly realise that Australia has its own native Hibiscus species plus a number of other similar genera. Here's a very brief introduction to this family.....
The family Malvaceae (pronounced Mal-vay-see) is one which contains a number of plants that we are very familiar with, but also a large
number which will not be familiar to us. It is widespread throughout the world, having some 75 genera and about 1500 species in total. It is generally represented in tropical and temperate regions.
In some countries it is known as the Mallow family, but we are much more familiar with it as the Hibiscus family. Apart from the well known Hibiscus genus, other genera which may be familiar are - Abelmoschus, Abutilon, Gossypium, Lagunaria and Thespesia. Some of the less well known members are - Pavonia, Sida, Urena, Alyogyne.
The family contains plants which are economically very important, such as cotton (Gossypium hirsutum) and others such as the Rosella, used for jam. Some of the Australian members can be used for jam and others as salad items.
All members have a simple flower design, and it is a feature of many species that the flower is large and showy. The exotic Hibiscus is a typical example of the flower. However, many of the hybrid varieties now sold have been altered to a complex or 'double' flower for commercial purposes. Many of the native species have a darker or contrasting centre in the flower, e.g. Gossypium australe, Hibiscus meraukensis.
Seed capsules are usually dry, and often prickly, opening to drop mature seeds.
Members of the family range from small, fleshy groundcovers or climbers, such as Abelmoschus moschatus, to large shrubs or small trees, such as Hibiscus tiliaceus.
From "The Native Gardener", the newsletter of the Townsville branch of the Society for Growing Australian Plants, August 1995.
See the article "Alyogyne- An Update" in this issue for further information on the genus Alyogyne.
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When is a Plant a Weed.....
and when is it a useful volunteer? Jan Hall tackles a growing problem.
After consulting environmental weed lists and balancing this information with your own observations, the answer to this question can only be decided at the local level.
For much of the year. our garden is set in dry, hard clay and after a few years even the improved soil of raised beds has settled back to an 'undiggable' state.
Ours is not the best of garden sites so it can be useful when something that we have planted self-seeds and fills the spaces.
We watch and see what happens.....
Some, such as Dianella callicarpa, are suspect and altogether too keen.
It may take several years and the help of birds before introduced Australian plants really show their colours.
Enchylaena tomentosa, 'Ruby Saltbush', in the prostrate form just grew quietly for 15 years. Then it learned of the presence of other forms (which we have planted) which have all taken off. The pretty berries are transported by our resident crested pigeons and germinate by the thousands. It's almost indigenous - but not quite.
Others with the same tendencies are Rhagodia sp. (saltbush are at home in our area.)
Solanum lanciniatum (Kangaroo Apple) - without water - grows quickly looks lush and green and has attractive dark purple flowers. We select the useful 'volunteers' and weed out the others. So far this species has remained inside the fence of our 1.5 hectare garden site.
Sollya heterophylla is a horror in many places but, although we get a few seedlings, for us this plant has not 'ventured out'. I wonder if the fine leaf, dark blue form (which has never seeded for us) would be generally acceptable.
Over 25 years, I have developed quite a long list of self seeding plants but, away from our watered garden, most are not a problem. Granted, our dry climate keeps many in check.
We don't have natural bush next door but we do need hardy plants.
A self sown Grevillea has a much stronger root system than a cutting-propagated plant of thie same species and there are no local grevilleas in our area from which a hybrid population could be developed.
So. before we accept that all plants listed as invasive must not be cultivated, maybe the conditions in your area are likely to be such that the plants under review might not pose any threat but will in fact be a perfect - and environmentally safe - complement to your garden.
From "Growing Australian", newsletter of the Australian Plants Society (Victoria), September 2002.
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Growing Sturt's Desert Pea
This is one of Australia's most spectacular wildflowers but it often poses a challenge to successful cultivation. Anne and David Rees prove that it's not impossible!
We have tried growing Sturt's Desert Pea (Swainsona formosa) three times in the last four years and twice we have been successful. We don't attempt to grow these plants in the ground but always in a tall concrete pipe in a mixture of half-and-half of good potting mix and river sand. Strangely enough, in the first year that we grew this beautiful plant (in 1996), when we were newcomers to growing a lot of Australian plants, this was the year when we had the most success.
The first Swainsona formosa seeds were bought from a general nursery and the most recent seeds came from a native plant nursery. The second time we tried we used seed from our first year's plants.
Before planting the seed must be treated. The method we use is to place the seed in a pyrex bowl and pour boiling water over it. We don't do this just the once, but twice over a period three days. Any seed that has floated to the top is discarded: the remaining seed is then planted. In the three years that we have grown Sturt's Desert Pea we have always planted the seeds in early September. Not all the seed that has been planted has germinated each time, but in our first year most of the seed did germinate.
In the second year (1997), we used two tall concrete pipes. Seed was planted on September 6; on September 23 the first small plants were showing. Initially the seedlings grew well but around the middle of October we noticed that insects were eating the small plants. We sprayed the plants, using a mild natural spray made from cloves, but this didn't work and by the middle of November there were no plants left at all.
After this failure we didn't attempt to grow Swainsona formosa in 1998, but in 1999 we tried again. Twelve seeds were put in to soak on September 4; on September 7 two were discarded because they were floating, and the remaining ten were planted. Two small plants were showing on September 12 and one more a couple of days later. Because of this poor germination, another ten seeds were soaked and then planted. Again we had poor germination results, only another three seedlings came up. These six plants grew well and the first flowers appeared on January 9.
We fertilise the plants every two weeks with a half strength watering of Aquasol. We water the plants about twice a week in normal weather; on very hot days we water lightly every other day.
These plants have a long root system. When we removed the plants from the pipe at the end of the first year, we found that the roots had grown down through the pipe and were beginning to go down into the soil below. The pipe that we use is about 60 cm high.
Although we seem to be getting mixed results, when we have been successful it has been really pleasing.
This year we have grown the one pipe of Swainsona formosa, in a group with some Actinotus helianthi (flannel flowers) and Wahlenbergia stricta (tall bluebells) in terracotta pots and a Blandfordia punicea (Tasmanian Christmas bells) in a small concrete pipe. We have been pleased with the picture that this arrangement of plants has made.
And among these plants we have a water bowl in the top of another concrete pipe. Often, early in the evenings, Superb Fairy Wrens come to the water bowl for a bath or young Gang Gang cockatoos arrive for a drink. And this really does complete the picture.
From "Growing Australian", Newsletter of the Australian Plants Society, Victoria, June 2000.
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More on Growing Sturt's Desert Pea
If Anne and David Rees' methods aren't right for you, Betty Rymer has some more suggestions to get you started.....
Every true gardener likes a challenge.
Over the years we have tried many ways of growing Sturt's desert pea - some successful some not. The following method we have found most rewarding - getting many blooms on the plants.
Remember these plants grow naturally in hot dry areas and are often found in a depression that may hold some water.
In April the seed was soaked overnight in hot water and then planted in peat pots filled with a well draining soil mix - 3 seeds to a pot. Germination is quick, but watch and do not over-water or you will get fungus problems. To be safe pour some fungicide through the pots.
When the seedlings are about 7.5 cm high, place these peat pots in a large 30cm pot - 3 peat pots to one large pot. This eliminates any root disturbance. You are sure to loose some plants and this ensures survival of enough plants to give a good show.
These pots are kept off the ground, facing north and under the eaves so no rain gets on the leaves.
Watering was in fact always feeding - a half strength solution of Aquasol or the like - carefully watering the soil around the plants and not on the plants themselves.
These plants flower in October-November and humidity in Sydney around Christmas always gives trouble since these plants come from places of dry summers in Western Australia, South Australia and western New South Wales.
Have a go, they are worth growing!
From "Native Plants for New South Wales", newsletter of the Australian Plants Society (NSW), July 2002.
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Happiness is a Hibbertia
Hibbertias are the sort of plants that can fill a host of different roles in a garden - Norm Cornwell explains why there is a Hibbertia for almost any situation or circumstance.........
What is the first thing that comes into your mind about the following colours: red. blue...... green, and yellow? I thought of blood, sky. grass and..... hibbertias.
Yes - hibbertias (however sunshine and warmth were a close second and to me that's what hibbertias are).
Most hibbertias are natural to Australia only and most of them have bright yellow blooms. There are. however, a few plants that can grow outside of Australia and there are some plants with orange or coppery blooms.
No garden (whether native or exotic) is complete without a Hibbertia and listed below are just a few that could meet your requirements.
You have either a shed, fence or wall that needs covering, or perhaps large tree stump that cannot be moved. Or what about a steeply sloped area on which it is difficult to grow other plants?
Solution: Hibbertia scandens, snake vine
A narrow bed along a driveway where you wish to conceal a fence?
Solution: Hibbertia cuneformis, cutleaf guinea flower or try Hibbertia scandens - providing you put some support up for this.
Where space is limited e.g. small gardens, units, flats or no gardens at all.
Solution: Pot or tub specimens such as Hibbertia microphylla (small-leaf guinea flower), Hibbertia obtusifolia (hoary guinea flower) or Hibbertia serpyllifolia (thyme guinea flower).
Something that could be grown in a garden that could keep weeds down to a minimum, but would not unduly smother or compete wilh most of the other plants?
Solution: Hibbertia dentata, twining guinea flower.
You have an established garden but it seems to be lacking 'that something'.
Solution: Hibbertia stricta (erect guinea flower), Hibbertia sericea (silky guinea flower), Hibbertia dentata (twining guinea flower).
You would like a Hibbertia when not in flower and just want some nice foliage.
Solution: Hibbertia cunninghamii (syn. H.bracteosa), Hibbertia grossulariifolia (gooseberry-leaved guinea flower).
You wish to grow the difficult ones.
Solution: Hibbertia stellaris (orange stars), Hibbertia prostrata (bundled guinea flower).
To get more information about these plants.
Solution: Encyclopaedia of Australian Plants Vol 5 by Elliot & Jones (Lothian 1990) and Australian Native Plants by Wrigley & Fagg (Collins 1979).
From "Growing Australian", newsletter of the Australian Plants Society (Vic), June 2002 (originally from the Hibbertia Study Group newsletter).
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Basic Propagation from Seed
Many Australian native plants are easily grown from seed and it's a great sense of accomplishment when you can plant out species that you have propagated yourself. Len Coe has the details....
Most native plants can be grown from seed and will germinate most of the year, but autumn and spring are the best times. This is because extreme temperatures can be avoided.
Seeds can germinate in any reasonable mix, but better results will be achieved by using a good quality one. This can be made up of two parts coarse river sand, one part peat moss, and one half part perlite (a good alternative to peat moss is the more environmentally friendly coco peat). This makes a nice free-draining mix with some moisture retention and the right texture that helps when pricking out seedlings (pricking out is the separation of a mass of germinated seedlings in punnets into individual plants in small pots).
Place the mix in punnets or individual tubes depending on the seed being planted and slightly firm down. Fine seed can be planted in punnets and larger seed in tubes depending on species. Examples of fine seed are Callistemon, Melaleuca, and Eucalyptus and large seed species are Hakea, Banksia, and Grevillea, but exceptions can be found.
Sprinkle seed lightly on lop of the medium and cover lightly with pure river sand. This will help keep the seed in place and avoid being washed away when watering. It also allows the seed to breathe. A general rule is to cover the seed with a layer of sand the same thickness as the seed.
Punnets must be kept slightly moist, in a warm sheltered position, with plenty of light but no direct sun. Germination time varies depending on species. Eucalypts will germinate within 10 days, whereas hakeas might lake up to 6 weeks. Some species take from months to years!
Once seedlings start growing, they will get to a stage when they need pricking out into individual tubes. It is best to do this when they are quite small but big enough to support between thumb and finger or held gently by the cotyledon leaves (these are the small leaves which emerge first). This is best done in a mild temperature (e.g. drizzly day) as you are dealing with soft sensitive baby plants.
Gently hold the seedling with its root hanging in the middle of the tube, fill the tube with mix and firm down gently. Water immediately and keep in similar conditions to where they were germinated.
As they grow they should be slowly hardened off to sun (which means exposing them to sun for short periods of time, and gradually increasing this exposure time) and also will benefit from liquid fertiliser such as Aquasol. Once the seedlings are growing and healthy they may be transplanted into larger pots or the garden.
This is only basic information on propagation and you will gradually fine tune these steps to suit your own individual conditions.
Finally, it is important to note that a plant grown from seed will not always be identical to its parents. The only way to guarantee an identical plant is to grow it from a cutting.
From the "Bulletin", newsletter of the Queensland Region of the Society for Growing Australian Plants, September 2002.
For further information on plant propagation, see our web site.
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Australian Plants online - December 2002
Association of Societies for Growing Australian Plants