Smoke Germination article (partial) - LONGish

John Taylor (
Thu, 19 Jan 1995 16:47:40 +1100

>I'd be interested in a summary of the smoke treatment
>article if you have time to post it. Thanks!
>in NC

I'll post it to everyone...

"Smoking Out The Natives" by Malcom Campbell - in "Gardening Australia"
magazine January 1995.

" We all know that smoking is a health hazard, but fortunately 'smoking' your
native plants in the garden is not. Dr Kingsley Dixon and Shauna Roche at the
Kings Park Botanic Garden in Perth, WA, have been conducting trials to find
Australian native plant species that respond to this germination mechanism.
They have also been testing some Californian genera, with similar results
As a gerneral rule, it seems that the smaller seeds break their dormancy
when fumigated with smoke. The smoke does not appear to need any particular
component, but tests have mostly used bush leaf litter as fuel. Following
trials in the Kings Park greenhouses and Alcoa's Marrinup Nursery near
Jarrahdale, the experts took their tents to the Kalamunda bush and tried the
technique _en situ_. (That's _botanique_ for 'in the field' or, if you are
a Latin scholar, it means 'in that position'.) The trials exposed s range of
native plant seeds in propagation flats to smoke for 30 minutes, 60 minutes and
90 minutes respectively. Though the time required for germination varied
slightly from species to species, it was found that, generally, 60 minutes gave
good results for all species that responded to smoke.
Dr Dixon and his team have now germinated over 70 species of Australian and
Californian plant that have, up until now, proved to be very difficult to
germinate from seed. Although only six _Verticordia_ species have been tested,
they all responded to the smoke treatment. As a nurseryman, I wasted many
hours trying to strike a range of splendid _Verticordia_ species with the
result that only a few took root and subsequently died in their tubes - so the
hope of growing these lovely 'feather flowers' from seed is a real boost to
keen native plantsfolk."

(Discussion about nice native species deleted to reduce length...)

" We all know that fire encourages many of our terrestrial orchids to flower,
because of the release of ethylene from the soil. We know that banksias need
the heat of a fire to char their woody seed cones so that, when the fire has
passed, the cooling cones can release their winged seed. Many of the legumes
such as _Hardenbergia_, _Kennedia_, _Acacia_ and _Hovea_ species rely on fire
to crack their hard seed coats, then germinate with the rains that follow.
For some genera, the fire mearly reduces the competition for light and
nutrients, giving the opportunistic plants a chance to grow.
Australia has approximately 20,000 Australian native plant species. It is
encouraging that, of the 200 tested by Kings Park, 70 have shown a positive
response to smoke treatment. There are literally thousands of 'difficult-to-
propagate' native plants worthy of growing in our gardens. Who knows which of
them might respond to smoke germination? It's certainly worth a try.
Dr Dixon, who is Assistant Director of Science & Education at Kings Park, West
Perth, WA 6005 would love to hear of your successes, either by mail or by fax
on (09) 322-5064, so why not give it a go?
I can think of some fairly simple methods you might use at home in the
propagation shed (using an old camping tent, perhaps?) which are similar to
smoking fish - but I'll leave you to decide on your own methods!" >:-(

" The ideal native plant seed-raising mixture is: 8 parts triple-washed
sand, with 1 part of fine peat and 2 parts of perlite.
The seed is surface-sown and covered only with sharp sand to the
of the seed. This will result in an incredibly thin layer of media for
most fine seed natives. In the really dry areas of Australia, fine
gravel of two-mm screening or sharp dry sand make the best surface mulch
for seed sowing. Water initially by immersion rather than overhead
until germination has occured. Otherwise, because of the surface
tension of the water, you might wash the fine seed away. Light
shadecloth is all the protection required. A glasshouse in January is
seldom needed, unless you garden in the coldest parts of Australia."

There is an article on this topic (the original...) "Smoke - A New
Process for Germinating Australian Plants" by S. Roche, R. Dixon & J.
Pate, two page article in "Australian Horticulture", 15 Sept-14 Oct
1994, published by Ramsay Ware Stockland Pty Ltd, Rural Press Victoria,
PO Box 160, Port Melbourne, rrp. $4.80 at newsagents. (Now they tell
me... I'll see if I can get hold of a photocopy of this article from
RMIT's library when I go back...)


| John Taylor [Catweasel] | Royal Melbourne Institute of Technology |
| | Department of Applied Physics |
| | Melbourne, Victoria, AUSTRALIA |