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The following have been selected from the questions received on the SGAP World Wide web site over the past few months. You're welcome to comment on any issue concerning Australian native plants....growing, propagating or appreciating (even loathing!) ... anything.
If necessary, bung a message in a bottle if your net connection goes down!!
....and, if you'd like to contact any of the correspondents and no email address is listed, please feel free to do so through the editor.
Reluctant Christmas Bush
Can anyone help me ?
I have been trying to propagate NSW Christmas Bush (Ceratopetalum gummiferum) from cuttings and I have tried a variety of hormone mixes and potting mixes with very little success. I am still trying but getting a little discouraged. Has anyone had any success and how? Any assistance greatly appreciated.
Is Christmas Bush really so hard to grow from cuttings?
This letter first appeared in the Australian Plants online Newsletter. The following detailed response from Gemma Amos (Research Assistant, NSW Christmas Bush Project at the University of Technology, Sydney) might interest others. Gemma is working with Dr Krystyna Johnson, on a project entitled "The Development of Christmas Bush as a cut flower crop for both export and domestic markets". Part of this project is concerned with the development of propagation technology; ie. seed germination, cuttings and plant tissue culture.
The NSW Christmas Bush, Ceratopetalum gummerifum is widely grown as a source of cut flowers at Christmas time in Australia.
Select the thumbnail image or plant name for a higher resolution image (25k).
"Christmas Bush is difficult to strike from cuttings and often the roots take a long time to form. Success has been reported with "Clonex" purple Gel with variable results. Our own experiments show that using "Rootex" Liquid or "Rootex" Powder is better than no treatment at all. Our results, however, vary from 20 to 90%. This may be due to the age of the material, thickness of stems, health of plant etc.
We have also tried using ancymidol and higher concentrations of IBA, but with not much success.
We are currently looking at the effects of different times of the year on the success of cuttings. Cuttings are taken from 2 commercial plantations in Kemspey and also from the NSW Agriculture Field Station at Somersby. Using the top 70mm of a stem, the cutting is dipped into Rootex Liquid preparation (1 part Rootex:1 part water), air dry for 30 seconds and place in media. We use a commercial style potting mix (1 peat:1 perlite:1 open coarse-gravelly sand) and place the cuttings in a fogging tent with bottom heating. Cuttings are fertilised fortnightly and are assessed after 8 weeks.
We commenced this trial at the beginning of the year and to date, the best time to take cuttings appears to be late January. Some growers however have told me that October is also a good time.
Our project commenced last year, and is part of a 3 year collaborative grant with NSW Agriculture. Before its completion, we hope to look at other aspects of propagation, such as the most most effective media to use,
length of cuttings etc. We also have a web page, which describes our project and which will be updated in the near future to include our results so far. The address is:
Should you require any further information, please do not hesitate to contact me. Hopefully, by the completion of the project, our work will be able to help cut flower growers, the nursery industry as well as other interested growers of Christmas Bush.
By any other name.......
Congratulations on an informative site.
I am looking for information relating to the growing and propagating of sandlewood in Australia. Perhaps you could point me in the right direction?
John Wrigley replies:
"Sandalwood is a name that covers several species.
Santalum acuminatum is one species that is being grown commercially for its fruit and is also known as wild peach or sweet quandong. It is wide spread in arid or semi-arid Australia. Considerable research has been done on this species by the CSIRO centred in Mildura and Sunraysia Nurseries, Gol Gol, NSW has been growing it commercially for some years.
Select the thumbnail image or plant name for a higher resolution image (42k).
Photo: Horst Weber
Santalum lanceolatum is known as northern sandalwood but as far as I know has little commercial value. It has been grown at the Australian National Botanic Gardens, Canberra.
The third species is Santalum album from the Northern Territory and which was exported for many years to China for its aromatic timber. Commercial cutting of the species has been stopped for many years but the Northern Territory Forestry Dept. has a plantation near Kunnunurra which they are maintaining but I am not sure how much research is currently going on. I suggest you write to the department for more details.
Hope this is of some help to you.
I have read The Callistemon Page with great interest as I live in
England and have just purchased (at great expense) a Callistemon citrinus and was afraid of pruning it.
The gentleman at the garden centre where I bought it said to prune behind the existing flower once it had grown over (just as you state on your site). Another gentleman at the RHS (Royal Horticultural Society) said that if I did this I would get no flowers the next year. This put me into a bit of a dilemma but having read your Callistemon page I think I will prune behind every flower. I just wanted you to confirm that this would be the thing to do and that the citrinus does not have a weeping growth habit. Is it to be pruned right after flowering (as the seeds are now hard and brown) or later in the season?
Diana Groot Copp
Well...both of them are right!
Callistemons flower on terminal shoots with each year's flowering occurring on the branch extension from the previous year. Pruning the spent flowers does a couple of things:
- It prevents the formation of the seed pods which a lot of people find unsightly (I like them!)
- It forces the stems to branch and produce more flowering stems than would normally be the case.
However, if you prune too late in the season, you may be pruning off material that is already forming flower buds for the next year (even if you can't actually see them). So, in this case you may well miss out on a season of flowers.
So the idea is to prune as soon as the flowers finish - I wouldn't leave it more than a month - and, if the seed pods on you plant have turned brown, I think it's probably too late. I'd leave it for this year - you can always prune back two years of flowering after the next season.
As for the growth habit...no, C.citrinus is normally upright. C.viminalis is the weeping bottlebrush.
Leatherwood in England
I live in Devon, England and although my garden is well established with some quite unusual plants/shrubs etc, I've currently added a few more. Our soil is very acid and boggy in places, and I've recently planted a Eucryphia Cordifolia Lucida, which has just started to flower (it's summer here now). I'm interested to find out if this is a native Australian plant. I stumbled across your web site while searching for info for some of my new plants. The region of England I live in is one of the warmer parts of the UK, (altitude around 1,000 feet), but in winter we have sub-zero temperatures and sometimes quite a lot of snow.
Any information or chat will be gratefully received.
Yes, Eucryphia is an Australian genus but species also occur in Chile. There are several species but the most well known is E.lucida which is a native of Tasmania. It's called "Leatherwood" and is famous for the highly distinctive, perfumed honey it produces....this might be available in the UK in speciality stores.
I don't know about the "cordifolia" part of the name. It's not used here, as far as I know.
Let me know if there is any specific info you would like to know about the plant.
A rash of grevilleas...
I have several Grevillea "Robyn Gordons" in my backyard and they are fantastic!
When I first planted them (about a year ago) I noticed on the info tag that they might cause skin irritations if touched. I weeded several weeks ago and found that I got an itchy rash on my arms which was described by my doctor as an "allergic reaction to something" Is it possible the Robyn Gordon caused this? Do you have any further details regarding this issue?
Thanks for the great site!
You're most welcome...glad you like the site.
Yes, Grevillea "Robyn Gordon" is a known cause of irritation on susceptible people (me included). Other similar grevilleas can cause problems too. When working around these plants it's necessary to wear gloves, long sleeve shirts and long trousers if you are sensitive to the plants.
It's a bit of a nuisance but the plant is so good I think it's worth putting up with.
A friend told me saw on television that there is a plant that is fireproof. I asked if she meant if it heals burns like the aloe plant but she insisted she heard of a plant that doesn't burn. She does not recall the name of the plant, but she said she remembers it is from Australia.
Would you happen to know of any such plant? I am very curious about this.
There are no Australian plants that don't burn (other than aquatic plants!) although there are some that are regarded as "fire retardant" in that they slow down the progress of a fire. Many rainforest plants are in this category as are things such as saltbushes which have a high content of salt in their leaves and stems.
But I certainly haven't come across any plants that are literally fireproof.
And on the same subject...
Just how fire resistant are natives, in comparison with exotics, and which natives are more fire resistant?
The reason I ask is that we live in the lower Adelaide Hills and we are all native oriented (indeed indigenous, local, oriented) but we want to know what can be safely grown near a house, and what would actively increase a house's fire safety. We generally hear about hakeas, but are there others?
This is a good question and is one that I have had to deal with for a recent project I was involved with. There isn't a lot of information available and most is anecdotal. The Australian Flora Foundation is (I understand) sponsoring research into fire resistant natives so perhaps this will lead to some reliable info in the not too distant future.
There is some info on our web site.
This was compiled after the 1993 Sydney fires.
The best internet site I've come across is that by the Queensland Department of Natural Resources at:
One of the DNRs fact sheets (Number T51) is called "Using Fire-retardant plants for fire protection" and it deals with both exotic and native species. It's obviously aimed at Queensland readers but it's general enough to give a good guide for other areas.
The only thing is that it's in Adobe Acrobat format so you will need the Acrobat reader to view it. This can be downloaded from lots of areas.
Umbrella tree confusion
I live in France and I'm looking for information about Schefflera actinophylla.
When cultivating this tree indoor, directions are to let the soil dry before watering again (I have 15 books that give me those directions!!) But, as you indicate it, this tree comes from tropical rainforest where the soil doesn't have time to dry! So, why must I let the soil dry for S.actinophylla when I'm supposed to
keep permanent moisture for others species coming from the same area ?
Is this tree an epiphyte?
Thanks for any information (I'm writing a book about indoor plants and this plant gives me big problems).
I handed this one to John Wrigley, who replied....
"This species occurs naturally as a lithophyte or epiphyte in north Queensland. However, as it is commonly cultivated in Australia in other areas much further south, it is frequently seen growing in garden situations where it receives normal garden watering. In an open situation, it forms a tree and flowers and fruits well. The fruits are relished by birds and as a result, this species has become a weed in natural bushland in eastern Australia. Here it may also be seen as an epiphyte in local rainforest.
It is a very hardy plant and provided it is not kept very wet, it should be able to be cultivated in any good potting mix and given reasonable light and warmth in your northern winters.
Germinating Kangaroo Paw
Can anyone help? I bought a packet of kangaroo paw seeds from the shop at King's Park in Perth and sowed them using the smoky water technique. They are now coming through the potting mix, which seems like a miracle!
I read about the smoke water concept with great interest, and saw the experts at Kings Park creating it, so I tried to do the same. I burnt some greenish eucalypt leaves under a pot and next to a container of water. The
smoke was intense and lasted for about an hour, so I think the water took in some of the properties of the smoke.
My question is, how long do I leave the seedlings before I take them out of the one large pot in which they were sown and put them into their own pot or tube? They came through the surface of the potting mix 2 weeks ago, but are still very small, coarse shoots. I live in Melbourne, and can provide a sheltered, sunny spot if necessary.
Glad to hear you're having good results. I haven't used the smoke water method yet but it certainly seems to have a lot of promise.
Kangaroo Paws (Anigozanthos sp.) are fairly easy to transplant when they are large enough to handle - about 1 to 2 cm high. Just gently separate them - use a knife or similar object to lever them out of the large pot and firm them into individual small tubes (say 50mm dia) with a sandy mix and a few granules of slow release fertiliser. Keep them in a protected position and gradually move them into the open.
Select the thumbnail image or plant name for a higher resolution image (42k).
How high does it get??
I purchased a Melaleuca leucadendra for my front garden two years ago which was ticketed as growing to 5 metres high and 2-3 metres wide. I have since read information in various books stating that this tree grows to some 20 metres!
As a responsible gardener, I would like to confirm just how high this tree is expected to grow in the Sydney area (Sans Souci) as I would prefer to replace it before it becomes a problem.
Your advice is greatly welcomed and appreciated.
Well.... it certainly can get to 20 metres in its natural habitat which is the tropical areas of Queensland and the Northern Territory where it grows in well-watered locations. I would be very surprised if it reached anything like that height in the Sydney area. Although it's impossible to give a definitive answer, I would expect a maximum of say 7-8 metres or less. In short, if it were mine, I'd leave it!
Germinating difficult seeds
I noticed in a discussion of difficult seeds that it helped to put some species in running water to leach out inhibitors. People might want to try my trick. Use an old aquarium that has a regular aquarium pump in it to keep the water moving. Seems to work quite well, although I haven't tried it on any Australian species. I change the water periodically although its probably unnecessary. I also use goldfish bowls with aerators in them. That's really cheap....a few dollars at most. With those I change the water every day.
Richard W. Pitchers
That's an interesting variation that some people might like to try. The use of running water is most often mentioned in relation to Boronia, Eriostemon, etc but it's a bit impractical to place seeds under a running tap for a couple of weeks or more (and not environmentally sound either!). If anyone gives this a go, please let us know your results (good or bad).
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Australian Plants online - September 1998
The Society for Growing Australian Plants