Classification of the genus Acacia (in the wider sense) has been subject to considerable debate. It is generally agreed that there are valid reasons for breaking it up into several distinct genera, but there has been disagreement over the way this should be done. As of 2017, it is widely (but not completely) accepted that the section that includes the majority of the Australian species (including this one) should retain the name Acacia, whilst other sections of the genus should be transferred to the genera Acaciella, Mariosousa, Senegalia and Vachellia[].

Common Name: Swamp Wattle

General Information

Acacia retinodes is an evergreen much-branched shrub or small tree with an open crown; it can grow from 5 - 10 metres tall[]. Although it produces leaves as a seedling, llike most members of the genus the mature plant does not have true leaves but has leaf-like flattened stems called phyllodes[].
The plant is sometimes harvested from the wild for local use as a food. This is a widely cultivated, fast-growing but short-lived species with unobtrusive flowers[].
The plant has become naturalized in some areas of Hawaii[].

Known Hazards

The seed of many Acacia species, including this one, is edible and highly nutritious, and can be eaten safely as a fairly major part of the diet. Not all species are edible, however, and some can contain moderate levels of toxins[]. Especially when harvesting from the wild, especial care should be taken to ensure correct identification of any plants harvested for food[].
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.

Botanical References

, ,

Range

Australia - Victoria, New South Wales, Tasmania. Locally naturalized in S. Europe[].

Habitat

Occurs mainly in open forest in poorly drained soils inland from the coast[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	6.00 m
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Acacia retinodes is native to the warm temperate areas of southern Australia, with disjunct populations in subtropical Queensland. It can be grown outdoors in areas with mild winters and will survive occasional moderate frosts.
Prefers a well-drained sandy loam and a very sunny position[, ], but it also stands drought and wet well[]. Succeeds in any good garden soil, this species is said to be fairly lime tolerant[, , , ]. Succeeds in a hot dry position[]. Plants are fairly tolerant of salt in the soil and salt-laden winds[].
A very ornamental tree[]. It can flower sporadically throughout much of the year but with the main flush in spring and summer[].
The seeds of most acacia species can be quickly and efficiently harvested at full maturity without the need for any specialised equipment. Small seed-bearing branches can be cut and beaten on sheets, or bushes can be beaten or shaken directly onto large sheets[].
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[].

Edible Uses

Flowers - cooked[]. Rich in pollen, they are often used in fritters.

Seed[, ]. A pleasing taste[]. The seedpods can be up to 18cm long, containing seeds up to 6mm long[, ]. Acacia seeds are highly nutritious and contain approx 26% protein, 26% available carbohydrate, 32% fibre and 9% fat[]. The fat content is higher than most legumes with the aril providing the bulk of fatty acids present[]. These fatty acids are largely unsaturated which is a distinct health advantage although it presents storage problems as such fats readily oxidise[]. The mean total carbohydrate content of 55.8 + 13.7% is lower than that of lentils, but higher than that of soybeans while the mean fibre content of 32.3 + 14.3% is higher than that of other legumes such as lentils with a level of 11.7%[]. The energy content is high in all species tested, averaging 1480+270 kJ per 100g[]. Wattle seeds are low glycaemic index foods. The starch is digested and absorbed very slowly, producing a small, but sustained rise in blood glucose and so delaying the onset of exhaustion in prolonged exercise[].

The ground seed can be used to produce a high quality, caffeine-free coffee-like beverage[].

Medicinal

The bark of all Acacia species contains greater or lesser quantities of tannins and are astringent. Astringents are often used medicinally - taken internally, for example. they are used in the treatment of diarrhoea and dysentery, and can also be helpful in cases of internal bleeding. Applied externally, often as a wash, they are used to treat wounds and other skin problems, haemorrhoids, perspiring feet, some eye problems, as a mouth wash etc[, ].
Many Acacia trees also yield greater or lesser quantities of a gum from the trunk and stems. This is sometimes taken internally in the treatment of diarrhoea and haemorrhoids[].

Agroforestry Uses:

The extensive root system of this plant helps to prevent soil erosion[].

Other Uses

A yellow dye is obtained from the flowers[].
A green dye is obtained from the seed pods[].

A good quality tannin is obtained from the plant[]. Bark harvested for its tannins should only be taken from mature stems, and only when the sap is rising at the beginning of the growing season - which is when the tannin content is highest and the bark is most easily removed from the wood[].

A good quality gum is obtained from the trunk and branches[]. Similar to gum arabic (Vachellia nilotica)[].

The wood is prettily grained, tough, and durable[].

Propagation

Seed - best sown as soon as it is ripe in a sunny position in a warm greenhouse[].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[].
Cuttings of half-ripe wood with a heel, mid summer 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[].