Acacia mearnsii

Black wattle

Family: Fabaceae subfamily Mimosoideae

A tree to 10 m tall, with smooth bark.

Naturally occurs from Peats Ridge in NSW south, on the coast and tablelands divisions, to Victoria, Tasmania, and South Australia. It has naturalised in Western Australia. Found generally in wet sclerophyll forest, woodland and coastal scrubs.

Leaves are compound-bipinnate (jacaranda-type), to about 14 cm long; dark, dull olive-green in colour, with each leaflet/pinnule less than 4 mm long and covered in fine hairs.

Flowers are first produced in globular heads, to about 8 mm diameter, with up to 40 very small staminate flowers per head, pale yellow, and fragrant.
The heads are arranged in axillary and terminal panicles or racemes, mainly October to December.

Seed pods are broad-linear, to 10 cm long, and about 1 cm wide.

In the garden

Considered easy to grow in sandy to loamy soils. It is a longer-lived bipinnate wattle with a nice overall form.

It has become a bad weed in many places including South Africa and the Americas.

Acacias can suffer from a number of pests, including borers, scale, galls and leaf miners. Growing plants suitable to your local environment minimises these occurring.


Propagation is easy from scarified seed by covering with boiling water for 24 hours and discarding any seeds still floating on the surface.

Other information

It is a useful pioneer plant that quickly binds erosion-prone soil following the bushfires and as well fixes the atmospheric nitrogen in the soil.

The species may resprout from basal shoots following a fire. It also generates numerous suckers that result in thickets consisting of clones. Seeds may remain viable for up to 50 years.

Acacia – from Greek acis, meaning a thorn or “thorny”.
mearnsii – named after Colonel Edgar Alexander Mearns (1856-1916), a notable American ornithologist and field naturalist who collected the type from a cultivated specimen in East Africa.
Not known to be at risk in the wild.


By Jeff Howes