Prickly Acacia

(Acacia nilotica ssp. indica)

Prickly acacia. image: Paul Bolstad, University of Minnesota, Bugwood

Status of prickly acacia in Tasmania

  • 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
Images top & above: Prickly acacia bush, & close up of branch with flowers, © Paul Bolstad, Uni. 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 Biosecurity Tasmania on 03 6165 3777 to report this weed.
See also

Other useful links
Pest Genie

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