Propagating Useful Australian Plants for Dry Climates
The use of local plants in a hot, dry climate.
I qualified last year as a horticulturist. I have been working with the local council in Carnarvon. In the last year, I have moved over to a family business which covers all aspects from seed harvesting to propagation to landscaping, so we do the whole process. We are a small family business, but very specific for our area.
Carnarvon is about 1000 km north of Perth, in the arid zone. Average temperatures in the arid zone are 37 degrees and above during summer. Yearly rainfall is between 190 to 250 mm. Carnarvon's windy season is November-December with wind speeds over 30 km/hour by late afternoon. So, we come from extreme climates all year round. As you can imagine, the vegetation we have up there is very drought and wind tolerant, salt tolerant because we are right on the coast. Some years we have had up to 50 days per annum with wind speeds in excess of 40 km/hr. We have prolonged dry spells. It is common to go several months without rain.
We do have a diverse vegetation. We try to propagate things that are in our area. We need drought and salt tolerant species, so why go somewhere else to get them when they already grow in our region? We do a lot with mining companies, revegetation, landscaping, domestic and commercial. We try to get people to realise that not everyone has a great deal of time: up our way it is even harder to keep things going, basically to get it through summer.
Australian plants are useful in our area for shade and shelter for stock in pastoral regions. Generally we are trying to get people to use local species rather than importing other species from elsewhere. Plants from a nursery down south can take a long time to acclimatise to our region. It can take months, and sometimes we don't have that time to wait.
We have a lot of development going on up our way. There is Northwater Estate which is all dredge-fill. I am doing all the landscaping for people there. We need a lot of salt-tolerant species because nothing else will grow in the dredge-fill from the sea. The water pressure is quite low, and there is not a lot of water available. It is very sandy and well-drained, which is a good thing because the salt can be washed through.
Medicinal uses, edible uses, which we try to promote in our schools. There are a lot of Aboriginal corporations up our way. They share their information around: everyone knows what grows where. We take a lot of school walks through the local arboretum. We have a block of land about 24 acres which has not been cleared, just kept everything natural. We direct seeded into it to bring up annuals and different types of plants to show people the diversity of trees and shrubs in our area.
Aesthetic values: A lot of our plants are overlooked for their aesthetic values. Flora and fauna and foraging: most people would be familiar with the Sturt Desert Pea. It is quite a nice groundcover but it has been found to be quite difficult to grow in our area because people like the flowers and pick them, and don't leave them to set seed. Pykelia ? A native annual; we find carpets of it everywhere. It is very bright. That is the kind of thing we are trying to propagate. Crotolaria cunninghamia, the bird flower. It is quite unique because the flower resembles a bird. We use that in all our demonstrations with the children because it has a lot of nectar in it. They love to suck it out.
As I mentioned, these dry-climate natives are overlooked as landscaping plants, and they are not readily available. Generally, we only have one nursery, Plazas (?) in Karratha, which is great because they have a very similar idea. We get plants down from them, but they have slowed their production. A nursery in Geraldton, Yilgarn Traders, are good, have a diverse range of plants. And we grow all our own endemic species for our area, and propagate them. It is a pretty small operation at the moment. Our focus is to try to get the community to understand that bringing things from elsewhere is not always the best way. Why not look at home first?
Some slides: Brachycome, a climbing daisy common in our area. Carpobrotus, pigface, a groundcover in our area, quite a nice flower. The fruit is edible, tastes a little like apple.
As you can see, there are so many things that we just haven't looked at in our own area. We have been concentrating on our own things. We don't just do landscaping, we do seed harvesting and we take great quantities of photos of flora and fauna.
Recently we just had a species of bee identified in our area: the burrowing bee. It is quite a big bee and we had colonies of them. We sent some down to the museum and got them identified and used it in our 5-year environmental plan for a local group, to actually look after them. They burrow into roads, and have a close affinity to the distribution patterns of our Northern Blue Bells.
The propagating methods we use include heat treatment, cold treatment, scarification, smoke treatment, special coatings and direct seed sites that are not treated with any coatings. Not necessarily because of cost but because we have had great viability without treating the seeds.
This is a species of creeper up our way which is quite rare, Synanchum floribundum (?). We haven't had great success in propagating it, but we are still trying. We are protecting the species we found in our area, and making sure that everyone is aware that they are endangered.
Heat and cold treatment: we use an oven, hot water, direct fire, air conditioning ducts or refrigeration for species such as Banksia ashbyi, which is our local banksia. And wattles. We make a small fire and place the banksia directly in it, and they pop open. Or put them in the oven. A common way to get wattles ready for propagation is to place them in hot water. This softens the hard coating of the seeds.
We use a small grinder for scarifying: you just grind the very tip off the seed. This allows it to germinate easily. Or, rub them along a file. Smoke treatment: you can use smoked water which is commercially available. We haven't used it because we have a simpler version that doesn't cost us anything. All we do is make a fire in a drum, let the fire burn down, put the meshes or mesh covered racks in with the seeds on them, and place something over the top to block the smoke. This has worked well for us.
Where the use of Australian plants can be applied:
- In pastoral regions, for forage for the stock to eat. I don't encourage that, but it is an option.
- Gardens, out in pastoral regions that are quite isolated and don't have a great deal of water.
- Shade, for obvious reasons.
- Aesthetics, there are a lot of wildflowers out in the pastoral regions, promoting that for tourism, ecotourism tours. Everyone is getting interested in that, which is a good thing.
I do a great deal of landscaping, my main focus. Water harvesting for mine site areas. We work for quite a few large mining companies. They like to regenerate the site back to its normal state, so we have to pick the seed locally and regenerate the site, which keeps all the dust down, they don't have to water it. It looks after itself.
Domestic landscaping which is low-water and low-maintenance for those who have little time. They like to be able to go away for weeks and no one has to look after the garden, they can just leave it. We call that the Lazy Man's Garden. We have one and it is fantastic.
Q. Plants resistant to wind?
A. Logically, they have a strong trunk, and they don't fall over or disfigure from the wind or the salt. We use a species of local acacia for windbreaks. It comes out as a large shrub and is not bothered by wind or salt. The local plantations have used casuarinas. They are starting to chop those down now, because they are getting into the water resources for the crops.
Q. Will your local species grow in dry southern areas?
A. The trouble there is with fertilisers. A lot of our plants are a bit touchy. We have planted things in Normandy and the mid-west region.
Q. You mentioned edible plants: can you think of any that might be developed?
A. Stylobasium, quandongs. Stylobasium, the pepper bush, is quite an interesting one. We have quite a few sandalwoods, which we protect. Many edible fruits are very small. Commercially, probably timber is of more interest than fruit. There is a current bush, a Scaevola, known as a fan flower, has a small fruit. I think if you feed them up well, they will grow bigger.