Acacia cowleana

Acacia cowleana, commonly known as Halls Creek wattle, and other names in Australian Aboriginal languages, is a species of flowering plant in the family Fabaceae and is endemic to northern Australia. It is an erect, openly branched, sometimes spindly shrub or tree with leathery, more or less sickle-shaped phyllodes, spikes of bright golden yellow flowers and linear, papery to leathery pods.

Description

A shrub or small tree. It grows 5 m tall. There are prickles along the stem. The leaves are twice divided and there are 8-18 pairs of pinnae. There are up to 50 pairs of pinnules on each pinnae. The flowers are yellow. They are in large clusters at the ends of branches. The pods are flattened.

Edible Uses

The seeds and pods are edible. Seeds are cooked and can be used in the same ways as other small legume seeds; they are also ground into a powder and used as a flavouring in desserts or as a nutritious addition to pastries and breads. The pods grow up to 75mm long and 3.5–5mm wide, containing dark brown to black, roughly oblong seeds around 3.5–5mm long. Acacia seeds are highly nutritious, containing approximately 26% protein, 26% available carbohydrate, 32% fibre, and 9% fat. The fat content exceeds that of most legumes, with largely unsaturated fatty acids contributed mainly by the aril. Energy content averages 1480 ±270 kJ per 100g. These seeds are low glycaemic index foods — starch is digested and absorbed slowly, producing a small, sustained rise in blood glucose and helping to delay the onset of exhaustion during prolonged exercise.

Traditional Uses

The seeds are ground into flour and mixed with water then eaten raw. (Damper made from the seeds is claimed to cause headaches.)

This uses section is brief — help expand it

Medicinal Uses

Like all Acacia species, the bark contains tannins and is astringent. Taken internally, astringents are used to treat diarrhoea, dysentery, and internal bleeding. Applied externally as a wash, they address wounds, skin problems, haemorrhoids, perspiring feet, some eye conditions, and are used as a mouthwash. Some Acacia trees also produce a gum from the trunk and stems that is taken internally to treat diarrhoea and haemorrhoids.

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.

Distribution

Usually occurs on sandy or stony soils. It suits warm semi arid regions. It can stand long periods of drought. It grows in Northern Australia. It cannot tolerate fire. It cannot tolerate frost. It can grow in arid places.

Where It Grows

Africa, Australia, Burkina Faso, East Africa, Kenya, Southern Africa, West Africa, Zimbabwe,

Cultivation

It grows best in areas where annual daytime temperatures are within the range 24 - 35°c, but can tolerate 12 - 45°c. When dormant, the plant can survive temperatures down to about -2°c, but young growth is more tender can be severely damaged at 0°c. It prefers a mean annual rainfall in the range 250 - 400mm, but tolerates 200 - 500mm. Requires a sunny position. Prefers a well-drained soil, though plants can tolerate seasonal inundation of the soil. Grows best in light to medium-textured soils, and is tolerant of low fertility. Prefers a pH in the range 5.5 - 7, tolerating 4.5 - 8. Acacia cowleana is not widely grown but should be a reliable shrub for temperate to arid climates in reasonably well drained soils. It has been successfully cultivated in California. A fast-growing but fairly short-lived species with a life span of 5 - 12 years. 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. Closely related to and previously confused with the tetraploid species Acacia elachantha. This species has been rarely cultivated compared to its close relative Acacia elachantha . 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. Carbon Farming - Cultivation: historic wild staple, new crop. Management: standard, coppice.

Propagation

Seed requires pre-treatment to break the hard seedcoat. Pouring a small amount of boiling water over the seeds and leaving them to soak for 12 hours is usually effective, as is making a small incision in the coat to allow water to enter. Germination rates of 40–80% occur in 6–15 days. Treated seeds are sown in germination beds, and seedlings are transplanted into polythene bags at the 2-leaf-pair stage. Seeds can also be sown directly into polythene bags. Seedlings should initially be kept at 50% sunlight, increasing to 70% once established. Generally 3–4 months are needed to raise seedlings to a plantable size of 25cm. Seeds stored in airtight containers at room temperature retain viability for several years. Cuttings may succeed but success rates can be well below 100%.

Other Uses

Acacia cowleana is a fast-growing, short-lived species commonly included in seed mixes for mine site rehabilitation. It can regenerate from basal coppice but more typically regenerates from seed, especially following disturbance. The wood is used as fuel and to make charcoal.

Production

Seeds are produced in late spring after flowers in May to August. It is a quick growing but short lived shrub.

Notes

There are about 1,350 Acacia species. Over 1,000 occur in Australia. Also as Mimosaceae.

Nutrition

Synonyms

Also Known As

Alerrey, Aliriya, Alkarta, Kalkardi

References (18)

• Bindon, P., 1996, Useful Bush Plants. Western Australian Museum. p 10
• Bonney, N., 1997, Economic Native Trees and Shrubs for South Australia. Greening Australia (SA) inc. Campbelltown SA 5074 p 5
• Cancilla, D., 2018, Ethnobotanical and Ethnozoological Values Desktop Assessment - Eliwana Project. p 9
• Cherikoff V. & Isaacs, J., The Bush Food Handbook. How to gather, grow, process and cook Australian Wild Foods. Ti Tree Press, Australia p 188
• Doran, J.C., & Turnbull, J.W. (Eds), 1997, Australian Trees and Shrubs: species for land rehabilitation and farm plantings in the tropics. ACIAR Monograph No 24. p 134

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