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Electronic Mailbox
 
The following have been selected from the questions received on the ASGAP 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.
Root Damage to Houses
In your Frequently Asked Questions, Question 12 lists Jacaranda mimosaefolia is listed as a tree with a vigorous root system and should be planted "at least 10 metres from underground pipes".
Valerie Swain in her book, "Australian Gardening" on page 243 suggests that Jacarandas have a "tidy root system" and can be planted as close as one metre to the house.
Please can you let me know who is right as I have recently planted a Jacaranda fairly close to my house.
I would also appreciate it if you could let me know if the Bracelet Honey Myrtle (Melaleuca armillaris) and Bottlebrush (Callistemon sp.)can cause problems to sewer pipes as I have three all within one metre to my sewerage pipes.
Hazel O'Dea
Australia
With due respect to the late Valerie Swain, there's no doubt in my mind that Jacarandas have a strong root system and can be a serious problem for underground pipes. You'll find this tree listed as a problem species by the Queensland Dept of Primary Industries - see their publication "Tree root problems".
Whether Jacarandas will be a problem for house foundations is a separate issue - I've seen quite large trees growing very close to houses without causing damage to concrete slab foundations but houses on piers might be more susceptible to damage. If your house is on piers, I'd be considering moving the plant.
Whether the Melaleuca and bottlebrush will cause problems to sewerage pipes depends on whether the pipes are clay or plastic. Neither species is probably vigourous enough to physically damage the pipes but, if the pipes are clay, the plants may eventually cause blockages. This is because even small amounts of settling of the pipes as the soils go through alternating wet and dry periods can cause movement of the joints sufficient to allow roots to enter. There shouldn't be a problem if the pipes are plastic.
Christmas Bush in Switzerland
We live in Switzerland and are the proud owners of a 1m 60cm NSW Christmas Bush (Ceratopetalum gummiferum) which we grew from a seed brought back from Australia some years ago. However, how to keep it??
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NSW Christmas Bush
Ceratopetalum gummiferum
Flowers (top)
Sepals (bottom)
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It is in a large pot and has, to date, survived every winter by being brought indoors. But the poor thing is always so unhappy inside and starts to lose its leaves almost from day one. By the time we can put it outside again (mid May to early November) its lost nearly all, though once it is outside it recovers again. There must be a better way though, of helping it over the winter months? We have it down in the cellar where the air is not so dry (i.e. no central heating) and leave the strip lights on during the day so that it gets at least a little light, but we're never quite sure how much water the bush needs nor when (and what?) the best time to feed it is.
So we would very much appreciate any advice you could give us!! Also, it has never yet flowered (neither the red nor the true whiteish flowers). Any chance that it ever would, do you think?
With many thanks and looking forward to hearing from you.
Alison Wiebalck
Switzerland
Good to hear from you and nice to know that NSW Christmas Bush is surviving in Switzerland.
I'm not sure that I can offer much useful advice because you're growing the plant in conditions that we have no experience with. NSW Christmas Bush is sometimes grown in a large container in Australia but it's never grown as an indoor plant. Generally plants like Christmas Bush which are native to temperate parts of Australia do not perform well when grown indoors for extended periods (as you have discovered). Plants native to rainforest areas seem to be more adaptable to growing indoors.
Your plant would probably grow better if it had more natural light and fresh air but, from what you say, that doesn't seem to be a practical option - I don't think that there is much more that you can do to help it.
As far as watering is concerned - the plant should obviously not be allowed to dry out. If it's losing leaves then its need for water would be fairly small while it's indoors. I would not be watering if there is any sign of moisture in the surface soil.
Regarding fertiliser - I'm guessing a bit here, but I'd suggest fertilising after spring. Normally the white flowers should appear in spring so fertilising before this might force the plant to produce foliage at the expense of flowers.
Christmas bush can take be slow to flower from seed - I wouldn't give up on its flowering just yet!
Melaleuca as an Environmental Weed
There are Melaleuca trees planted somewhere in Florida to kill off some other kind of growth. Those trees have gotten out of hand and are growing like crazy. Can you tell me if it is Melaleuca alternifolia? If not, which species is it?"
Yovette Bronson
USA
No..they aren't Melaleuca alternifolia. The species involved is Melaleuca quinquenervia, the broad-leaved paperbark.
Although M.quinquenervia is suitable for many areas in Australia, caution should be exercised in planting the species in tropical wetland areas overseas. As you mention, the plant has caused serious environmental damage in the Florida Everglades, USA, where it has spread uncontrollably.
You will find further info about these trees in the "Environmental Weeds" section of our website
Grafting Eucalypts
l was just wondering if someone can help me with an enquiry , l would like to graft a pink flowering gum and was wondering if l can use blue gum as the stock. Any comments would be helpful.
Raelene
Australia
Grafting eucalypts is a bit specialised and the people doing it commercially aren't advertising the root stocks they are using.
I would expect that you need a stock very closely related to the pink flowing gum - not any eucalypt will do.
Presumably your "pink flowering gum" is a form of the Western Australian Red-flowering gum - as this is a bloodwood, I would try to find a bloodwood that performs well in your district. For example, in Sydney I would consider red bloodwood (Corymbia gummifera), yellow bloodwood (C.eximia) or spotted gum (C.maculata) but these might not be suitable in your area.
I don't know exactly what species you call blue gum (there are several "blue gums") but it's probably not the ideal stock.
Telopea Wirrimbirra White
Are seeds from the Wirrimbirra White Waratah available on the market?
I am currently growing several Waratah species here in South Carolina (USA) and would like to attempt the white variety if they are available.
Peter Moeller
USA
"Wirrimbirra White" is a form of the NSW Waratah, Telopea speciosissima. I haven't seen any seed available but I don't follow seed lists very closely.
However, even if they are available I think the chances of getting white flowered seedlings would be small. The original white flowered form was a single plant growing in a red-flowered population. I'm no expert on genetics but I think red flowered offspring would be the most likely result.
Looking for Brown Boronia
In response to Carla Kiiskila's inquiry in the December 2001 issue of "Electronic Mailbox"...
I've run across a lot of people searching for brown boronia (Boronia megastigma) in various places on the web. It is available in the trade here in the USA, but predominantly in California and mostly sold at the retail level through nurseries. I've yet to see it listed on any online location.
I currently live in Washington state, just north of Seattle, but used to grow boronias in my nursery in California. It would definitely need winter protection here, though would do well on a warm patio in full sun in the summer.
Randy Linke
USA
Thanks for that advice, Randy. I guess Carla will just need to keep looking!
Germinating Calytrix
I am currently trying to grow some of the above seed but am having no success. Could you please give me some idea as to what needs to be done to actually get the little suckers to grow!!!!
Any assistance you could provide would be greatly appreciated.
Mandy Appelbee
Australia
The bad news is that Calytrix seed is extremely difficult to germinate.
The good news is that it's not impossible!
It's been some years since I germinated any, but I found that the only way to have any real success was to pregerminate the seed. This is done by taking a small plastic container (eg margarine container), putting a couple of layers of moist paper towel (or, better still, moist vermiculite) in the bottom, putting the seed on the towel, closing the lid and storing in a warm spot.
After a couple of weeks, check if there is any sign of roots emerging from the seeds - if not close the lid again and check in another week ....and so on. When (or if) germination occurs, carefully remove the germinated seed from the container and pot up into a small growing tube (leave the top part of the seed poking out from the top of the mix).
I found that the best time of year for doing this was autumn.
If you don't see any germination after a couple of months, the seed is probably not going to germinate at all.
There's a bit more on pregermination in the Plant Propagation section of our web site.
Pepper Tree
A friend of mine just moved to Arizona in the USA. She has an Australian pepper tree in her yard. She can't find out much about it. Can you give me some information? Is the pepper edible?
Thanks.
Unknown
Australia
Are you sure it's an "Australian" Pepper tree? There is an Australian plant called "Mountain Pepper" (Tasmannia lanceolata) but it's a rainforest plant from high altitudes and is not widely grown even in Australia. I would be very surprised if it would be successful in Arizona.
I think it's more likely that your friend has a plant called Schinus molle. This is commonly known as the "pepper tree" and is widely grown in Australia and in the western states of the USA but it's not an Australian native plant - it hails from South America. It's a medium tree to about 15 metres high with ferny, willow-like leaves. Unfortunately I have no information on whether the fruits are edible.
Incidentally, there's a bit of information on the "Mountain Pepper" in the article "Our Wild Foods to the World" in this issue of Australian Plants online.
Identifying Eucalyptus
I am a property owner in Central Victoria who is interested in studying Eucalyptus varieties and their identification. Can you please point me in the direction of a thorough web site, CD, or book?
Paul Whittaker
Victoria
The Eucalypt Page on our website is fairly general and it won't directly help. However, it includes a list of "Further Information" which includes references to good field guides and a CD-ROM known as EUCLID. The latter is a computer-based, interactive identification and information system. It allows the user to quickly and easily identify any of the 324 species and subspecies of Eucalyptus and Angophora native to south-eastern Australia, i.e. New South Wales, Australian Capital Territory, Victoria, Tasmania and part of South Australia.
A Native Grass?
I have recently planted a couple of native gardens to reduce some of the grassed areas at my home. While looking for plants, I came across a grass species called Festuca glauca. I don't know if it is a native grass or not. I have asked all my nurseries and they also don't know. Is it?
David Reid
Australia
To the best of my knowledge Festuca glauca is not a native species. There are native fFestucas (about 8 apparently) and there are about 5 exotic species that have become naturalised.
Elliot and Jones' "Encyclopaedia of Australian Plants" says that "a couple of the exotic species are grown as ornamental rockery plants". As I've never seen any native Festucia available for general sale, I strongly suspect that F.glauca is one of these exotics. However, my references aren't complete on this so I can't be 100% certain.
Grafted Banksia
Could you please tell me where I could purchase grafted banksias from Western Australia?
Neil Hort
Maleny, Queensland
Sorry but I have no idea.
Grafting of banksias has been under research for many years with limited success. Despite some recent reports that a breakthrough may have occurred, I have not come across any plants for sale.
I can only suggest that you keep in contact with specialist native plant nurseries in your area - you'll find a list of specialists on our website.
Eucalyptus for Floristry
I would like to learn more about the cultivation of Eucalyptus for use in a florist application. I know it is done in California. Is Florida (climate and soil) suitable for the volume cultivation of these plants?
Thank you for your help.
Bill Ahern
Florida USA
Unfortunately it's not a question that can be easily answered. There are hundreds of eucalypts - some are native to tropical areas but the majority occur in less humid climates. Whether the tropical species would be suited to floristry work, I really can't say.
The ones used most for florist work are those that can be coppiced so that they keep producing grey, rounded juvenile foliage. To the best of my knowledge, the most popular species for this are E.gunnii, E.morrisbyi and E.perriniana. These are all native to temperate, southern Australia and, while they may grow in tropical areas, I have no information on whether they would be sufficiently vigorous or produce suitable foliage.
Eucalyptus and Fire
I am a student of the forestry department of the Swiss Federal Institute of Technology, Zurich and have to write a "semester-work" during the next 3 months. As I've already visited your beautiful country and as I've got interested in eucalyptus, I decided to write my paper about "The influence of bushfire on the Eucalyptus".
First of all, I'm not rather sure which Eucalyptus species I'd like to write about. I hardly can remember the species a ranger was talking about on a tour in Undara Lava Lodge, Queensland. He told us something about an ironbark (?) which seemed to be resistant to fire (only once?).
I would be really interested in getting more information as more links, other works, experience...
Alexander Angst
Switzerland
This is a very topical subject as here in New South Wales we've just had one of the worst season's for bushfire on record. Much of the bushland in my area in western Sydney has been burnt but the eucalypts are already starting to show regrowth.
You will find general information on eucalypts on our website. In the "Further Information" section of that page there are quite a few links to other sites - some of which have information on fire.
Re ironbarks - there are quite a number of different species all having the thick, furrowed bark. These will usually regenerate after fire by sprouting new leaves from underneath the bark - this is not restricted to once only.
I hope this helps.
Illawarra Flame Tree....Poisonous?
Can you help?........
I am trying to find out if the Illawarra Flame tree (Brachychiton acerifolius) is poisonous. I have researched by name and included the word 'poisonous' and get all sorts of sites that say it is, but when I access the site no mention is made of it.
Maureen
Australia
According to Tim Low in his book "Bush Tucker"......
All of the Kurrajongs (Brachychiton species) "have nutty edible seeds inside leathery pods. The flame tree (B.acerifolius) often planted in gardens, is a member of this group, and it is easy to gather seeds from roadside trees to roast as treats"
The following extract from an article on bush foods says about the related species, B.populneus (Kurrajong) ....
"The tree bears large clusters of black leathery boat shaped pods which contain bright yellow to mustard coloured seeds. Itchy hairy fibre also surrounds the seeds and must be removed before use, which is a time consuming process. The seeds are very nutritious and are high in protein, fat, oil and some minerals. Once roasted and ground, they produce an excellent dark, rich flour with a nutty flavour. Kurrajong should be roasted before use, not eaten raw."
The seeds of flame tree also have the hairy fibre around the seeds and care must be exercised in removing the seeds from the pods.
Surviving in Arid Conditions
I was just wondering how Eucalyptus trees survive the arid temperatures in the outback where water is scarce. Could you please tell me?
Holly
Australia
There are several methods that are used by eucalypts to survive in arid areas.
The larger ones tend to grown along the banks of rivers. Although the rivers may dry up for many years, there is still sufficient moisture in the ground to keep the trees alive. The River Red Gum (Eucalyptus camaldulensis) is the common one that grows in this way.
Other eucalypts in dry areas have roots which can store water - some in sufficient quantities that they were used by Aborigines as a water source. Examples are the Water Mallee (Eucalyptus socialis) and the Ridge-fruited Mallee (Eucalyptus incrassata).
Germinating Bunya Pines
In the March 2001 issue, Chris Pullen of the UK inquired about methods of propagating Bunya Pines (Araucaria bidwillii). This is a response to that query....
Bunya seeds are very easy to germinate if fresh....once old they become much harder.
I germinate them in two ways. Either insert them pointy end down into good potting mix so that the top is just poking through the soil and if fresh they will begin to germinate in a matter of days. The second way is to place the seeds in a very shallow tray of water with the pointy end just in the water. After a few days a root will emerge. These can then be placed in potting mix as above. Once in the potting mix keep just moist, They will rot quickly if too wet.
Over the next few months the seeds will fall off leaving a little tuber in the soil. Around 9 to 10 months later a new shoot will emerge from the top of the tuber growing up the old remains of the first root which be now has shrivelled up, to emerge as the first shoot of the young tree. About 1 year after first planting the trees should be about 10cm tall. I always plant seed fresh which I collect oof local trees, leaving them no longer than a week after the cones fall. I have also purchased seeds from the Queensland Department of Primary Industries which have also had excellent germination results. They have a web site and send seeds mail order.
I hope this will help Chris.
Jeffrey
Sydney
Thanks for those tips - I'm sure a lot of readers will find them very useful.
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Australian Plants online - March 2002
Association of Societies for Growing Australian Plants
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