Acacia trinervata

Three-veined wattle

Family: Fabaceae subfamily Mimosoideae

An erect or spreading shrub growing to 3 m high.

It grows naturally in eucalypt open forest and woodland on sandstone and shale, between western Sydney and adjacent lower Blue Mountains, from about Wilberforce to Woodford.

Australian Wattles at least, can be broadly placed into 1 of 3 recognisable groups:

  • Group 1: Those that produce juvenile compound-bipinnate leaves and then change to producing adult-phyllodes which are modified-flattened petioles which form the foliage. This is combined with flowers produced in globular balls or heads (or ovoid heads). The heads can be singular in leaf/phyllode axils or arranged in groups.
  • Group 2: As for Group 1 but flowers are produced in longer rod-like spikes.
  • Group 3: Those that never produce phyllodes and retain the juvenile compound-bipinnate foliage into adulthood. These always produce flowers in globular balls (which are secondarily arranged into panicle or raceme-like groups in many cases).

This wattle belongs to Group 1.

The phyllodes (modified leaves) are very narrowly elliptic to linear with a pointed sharp tip, to 50 mm long and to 3 mm wide.

Very small staminate flowers are produced in globular heads with each head having up to 30 flowers. The heads are produced solitarily in the phyllode axils and are up to 8 mm in diameter.

The seed pods are to 12 cm long and to 3 mm wide.

In the garden

Not much is currently known about this species in cultivation. It may not have been trialled sufficiently or may be difficult to grow. It may be cultivated more widley in thr future.

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

Most wattles will die in a fire and regenerate from seed. Some species exhibit suckering from basal parts and roots.

Acacia is a highly diverse genus, with over 1500 recognised species (placing it in the top-10 most-diverse plant genera) occurring in most continents except for Europe. Australia has about 970 spp., most of which are endemic. There are also about 10 exotic species. NSW has about 235 recognised species. Some species have become weeds in other states outside of their natural range (e.g., wattles from Western Australia into NSW and vice versa).

Acacia – from Greek Akakia – which refers to an Ancient Greek preparation made from one of the many species; the name of which derives from akis, meaning “thorn” – referring to the thorns of species in Africa.

trinervata Latin for “three-veined” and refers to the three-veined phyllodes which are also pungent.

This species is not considered to be at risk of extinction in the wild – although it has a comparatively small geographic range.

NSW Flora Online (PlantNET) – Acacia trinervata profile page                https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Acacia~trinervata

By Jeff Howes. Editing and additional text by Dan Clarke.