Green Wattle
Acacia decurrens

Family: Fabaceae or Leguminosae

What it is like

Acacia decurrens is an evergreen Tree growing to 12 m (39ft 4in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 7. It is in leaf all year, in flower in April. The species is hermaphrodite (has both male and female organs). It can fix Nitrogen. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid and neutral soils. It cannot grow in the shade. It prefers dry or moist soil.

Height (m): 12

Where it is found

Sheltered forests, mainly on shales and sandstone. Usually on cool moist hills and gullies.

Australia - New South Wales, Tasmania, Victoria.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 2

Flowers - cooked. Rich in pollen, they are often used in fritters. A gum that exudes naturally from the trunk is edible and is used as a substitute for Gum Arabic in making jellies etc. It is insoluble in water and is of low quality. Larger quantities can be obtained by tapping the trunk. Some species produce a gum that is dark and is liable to be astringent and distasteful, but others produce a light gum and this is sweet and pleasant. It can be sucked like candy or soaked in water to make a jelly.. The gum can be warmed when it becomes soft and chewable.

Gum: can be chewed as a chewing gum or can often be used as a sweetener or thickening agent in foods.

Medicine

Rating: 1

The bark is astringent. It should be stored for 12 months before being used. Its main use is in the treatment of diarrhoea.

Astringent: Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.

Other

Rating: 3

A yellow dye is obtained from the flowers. A green dye is obtained from the seed pods. The extensive root system of this plant helps to prevent soil erosion. Often grown as a screen in Australia. The bark contains about 40% tannin. On a 10% moisture basis, the bark contains 36.6% tannin.

Dye: Plants that provide dyes.

Gum: Gums have a wide range of uses, especially as stabilizers, emulsifiers, thickening agents, adhesives etc.

Hedge: Plants that can be grown as hedges.

Soil stabilization: Plants that can be grown in places such as sand dunes in order to prevent erosion by wind, water or other agents.

Tannin: An astringent substance obtaied from plants, it is used medicinally, as a dye and mordant, stabilizer in pesticide etc.

Food Forest: Plants for Edible Forest Gardens and Food Forests.

Hedge: Hedge

Nitrogen Fixer: Plants that fix nitrogen in the soil

How it is grown

Prefers a light sandy loam and a very sunny position sheltered from strong winds. Succeeds in any good garden soil that is not excessively limey, it also succeeds in dry soils. Most species in this genus become chlorotic on limey soils. Plants tolerate temperatures down to about -5°c. This species is one of the hardiest members of the genus, it succeeds outdoors in the milder areas of the country, but even in Cornwall it can be killed back to the ground in excessively harsh winters. It will, however, usually resprout from the base. Plants require hot, sunny summers if they are to ripen their wood fully and flower freely. In Britain they tend to do best when grown in coastal gardens in a sunny, sheltered position that is protected from the wind. A fast-growing and very ornamental tree, it is closely related to A. dealbata. The cultivar 'Mollis' is notably resistant to honey fungus. 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.

Propagating it: Seed - best sown as soon as it is ripe in a sunny position in a warm greenhouse. Stored seed should be scarified, pre-soaked for 12 hours in warm water and then sown in a warm greenhouse in March. The seed germinates in 3 - 4 weeks at 25°c. 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. Cuttings of half-ripe wood with a heel, July/August in individual pots in a frame. Overwinter in a greenhouse for the first winter and plant out in their permanent positions in late spring or early summer. Fair percentage.

Best place to grow: Woodland Garden Secondary; Sunny Edge; Hedge;

Habit: Tree

Hardiness: 6-9

Growth: Fast

Soil: Light (sandy), medium

Shade: No shade

Moisture: Dry, moist

Things to keep in mind

Its other names

Local names

Synonyms

Mimosa decurrens.