Prickly Acacia

Status of prickly acacia in Tasmania

(Acacia nilotica ssp. indica)

Prickly acacia. image: Paul Bolstad, University of Minnesota, Bugwood
  • Prickly acacia is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of mimosa are prohibited in Tasmania.
  • Prickly acacia is also a Weed of National Significance (WONS).
  • The legal responsibilities of landholders and other stakeholders in dealing with prickly acacia are laid out in the prickly acacia Statutory Weed Management Plan.


What does prickly acacia look like?

  • Prickly acacia is a small, thorny and spreading tree usually growing to 5 metres, but which can grow to 10 or more metres in optimal conditions. The leaves are fern-like, around 30 to 40 mm long, and composed of 30 to 40 leaflets. A pair of stout spines, 10-50 mm long, grows at the base of each group of leaves in young stems.
  • Fluffy round clusters of golden yellow flowers occur in groups of 2-6 at the leaf base, and the seed pods are grey-green, covered in fine hairs and generally 100-200 mm long. The characteristic constrictions between each seed in the seed pod resembles a strand of pearls.
  • Spread is via seed. Seed can be spread in water. However most spread in Queensland has been by cattle which eat the nutritious seed pods.
  • See the WONS website for more information on identifying this weed.
Prickly acacia branch with flowers, image: Paul Bolstad, University of Minnesota, Bugwood
Image above left: Prickly acacia, image: Paul Bolstad, University of Minnesota, Bugwood
Image above: Prickly acacia branch with flowers, image: Paul Bolstad, University of Minnesota, Bugwood

Impacts of prickly acacia

  • Prickly acacia is capable of infesting vast tracts of grasslands and woodlands. The weed can severely reduce grassland productivity and restrict access to waterways.
  • Severe infestations can impact on native biodiversity.


Where does prickly acacia occur?

  • Prickly acacia is native to Africa (Ethiopia and Somalia) through to Pakistan, India and Burma.
  • On mainland Australia, prickly acacia occurs in Queensland.
  • Prickly acacia does not occur in Tasmania.


What you need to do

  • If you locate prickly acacia anywhere in Tasmania, or if you find a plant that you think could be prickly acacia, immediately contact your Regional Weed Management Officer on 1300 368 550 to report this weed.
See also
Weed Links and Resources

Other useful links
Pest Genie
Weeds in Australia - Weed Management Guide

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