
Acacia pycnantha
Acacia pycnantha
Safety & Hazards
Especially in times of drought, many Acacia species can concentrate high levels of the toxin Hydrogen cyanide in their foliage, making them dangerous for herbivores to eat.
Cultivation Details
A plant of the warm temperate zone, where it is found at elevations up to 800 metres. It grows best in areas where annual daytime temperatures are within the range 20 - 28°c, but can tolerate 5 - 35°c[1]. When dormant, the plant can survive temperatures down to about -2°c, but young growth can be severely damaged at -1°c[1]. It requires hot, sunny summers if it is to ripen its wood fully and flower freely[2]. It prefers a mean annual rainfall in the range 1,000 - 1,600mm, but tolerates 600 - 2,300mm[1]. Prefers a well-drained, rather poor sandy loam and a very sunny position[3, 2]. Succeeds in any good garden soil that is not excessively limey and also in dry soils[2]. Prefers a pH in the range 6 - 7, tolerating 5 - 7.5[1]. Most members of this genus become chlorotic on limey soils[4]. A fast growing but short-lived tree in cultivation[5]. It can often flower in its second year from seed[6]. This tree is the floral emblem of Australia[5]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[4].
Propagation
Seed - best sown as soon as it is ripe in a sunny position in a warm greenhouse[3].The dried seed of most, if not all, members of this genus has a hard seedcoat and may benefit from scarification before sowing to speed up germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing. Sow the seed in Spring in a greenhouse. As soon as the seedlings are large enough to handle, prick them out into individual pots and grow them on in a sunny position in the greenhouse for their first winter. Plant them out in late spring or early summer, after the last expected frosts, and consider giving them some protection from the cold for their first winter outdoors. Acacia seeds that have matured fully on the bush and have been properly dried have a hard seed coat and can be stored in closed containers without deterioration for 5 - 10 years or more in dry conditions at ambient temperatures. It is best to remove the aril, which attracts weevils and can lead to moulds forming. The arils are easilyremoved by placing the seeds in water and rubbing them between the hands, then drying the seeds and winnowing them[7]. Cuttings of half-ripe wood with a heel, mid summer in individual pots in a frame[8]. Overwinter in a greenhouse for the first winter and plant out in their permanent positions in late spring or early summer. Fair percentage[8]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Acacia+pycnantha>
Pollinators
Insects
References
- [1]Ecocrop — http://ecocrop.fao.org/ecocrop/srv/en/home ↩︎Basic information on a wide range of useful plants, plus details of environmental needs where available.
- [2]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
- [3]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
- [4]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
- [5]A Field Guide to Australian Trees. — Holliday. I. and Hill. R. · Frederick Muller Ltd. · 1974 · ISBN 0-85179-627-3 ↩︎A well illustrated and very readable book, but it does not contain much information for the plant project.
- [6]Australian Native Plants Society — http://anpsa.org.au/index.html ↩︎A series of fact sheets on Australian plants. Good photographs, brief description and information on uses, habitat, range, cultivation etc.
- [7]Potential of Australian Acacias in combating hunger in semi-arid lands — Rinaudo A.; Patel P.; Thomson L.A.J. · 2002 ↩︎
- [8]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
- [9]The Useful Native Plants of Australia. — Maiden J.H. · Turner & Co.; London. · 1889 · http://www.biodiversitylibrary.org ↩︎Terse details of the uses of many Australian plants and other species naturalised, or at least growing, in Australia. It can be downloaded from the Internet.
- [10]Economic Botany. — Hill. A. F. · The Maple Press · 1952 · ISBN - ↩︎Not very comprehensive, but it is quite readable and goes into some detail about the plants it does cover.
- [11]Flora of Australia — http://www.anbg.gov.au/abrs/abif/flora/ ↩︎The full information from the Flora of Australia - on-line. An excellent resource.
- [12]Wild Food in Australia. — Cribb. A. B. and J. W. · Fontana · 1976 · ISBN 0-00-634436-4 ↩︎A very good pocket guide.
- [13]Plants for Human Consumption. — Kunkel. G. · Koeltz Scientific Books · 1984 · ISBN 3874292169 ↩︎An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
- [14]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
- [15]Wild Food Plants of Australia. — Low. T. · Angus and Robertson. · 1989 · ISBN 0-207-14383-8 ↩︎Well presented, clear information and good photographs. An interesting read for the casual reader as well as the enthusiast
- [16]Nature's Colors - Dyes from Plants. — Grae. I. · MacMillan Publishing Co. New York. · 1974 · ISBN 0-02-544950-8 ↩︎A very good and readable book on dyeing.
- [17]Vegetable Tannins — Rottsieper. E.H.W. · The Forestal Land, Timber and Railways Co. Ltd. · 1946 · ISBN - ↩︎A fairly detailed treatise on the major sources of vegetable tannins.
- [PFAF]Plants for a Future — pfaf.org ↩︎