Photo guide to weeds

Mimosa bush (Acacia farnesiana)

  • Close up photograph of  the branches and yellow blooms of the Mimosa bush
    Mimosa bush flowers
  • Photograph of a Mimosa bush
    Mimosa bush

General information

Native to Central and South America, mimosa bush is a rounded shrub or small tree. Mimosa bush can be confused with the declared weeds mesquite and prickly acacia.

Mimosa bush is not a declared pest plant under Queensland legislation.

Overview

Scientific name Acacia farnesiana synonym Vachellia farnesiana
Description
  • Grows to about 3m, occasionally to 5m.
  • Branches grow in a zigzag shape and are usually grey-brown with prominent white spots.
  • Leaves are ferny, with 1-6 pairs of leaf 'branches' each with 5-20 pairs of narrow, rounded leaflets 4-8mm long.
  • Leaves are sometimes yellowish-green rather than pure green.
  • Thorns are found in pairs at the base of each leaf and can grow up to 10cm.
  • Flowers are ball-shaped, about 1cm wide, golden yellow to orange and grow on stalks.
  • Pods are dark brown or black and woody at maturity, with seeds embedded in the pith.
Habitat
  • Prefers dry localities, and loamy or sandy soils.
  • Forms thickets along watercourses.
  • Withstands drought well, is readily eaten by stock, and has good regrowth after grazing.
Distribution
  • Native to Central and South America.
  • Naturalised in Australia and widespread in Queensland.
Life cycle
  • Flowers autumn to early summer.
Spread
  • Spreads by movement of seed.
Impacts

Economic

  • Forms thorny thickets which hinder mustering and stock access to water.
Prevention

The best form of weed control is prevention. Treat weed infestations when they are small - do not allow weeds to establish.
Ways to prevent weed spread 

Control

Herbicide control

    Basal bark spray

  • Stems up to 15cm diameter, carefully spray completely around base of plant to a height of 30cm above ground level. Thoroughly spray into all crevices. Larger trees may be controlled by spraying to a greater height, up to 100cm above ground level.
  • Best time for treatment is during autumn when plants are actively growing and soil moisture is good.
  • Cut stump treatment

  • At any time of year, cut stems off horizontally as close to the ground as possible. Immediately (within 15 seconds) swab cut surface with herbicide mixture.
  • Bore drains

  • Seek technical advice regarding options for treating channels such as bore drains

See the mimosa bush fact sheet (PDF, 208KB) for herbicide control and application rates.

Biological control

  • There is no biological control agent available for this plant. However, mimosa bush is attacked by many native insects associated with Australian native acacias and other native plants. Sporadic dieback of mimosa bush has also occurred throughout western Queensland.
Declaration details
  • not a declared species under Queensland legislation but may be declared under local government law

Last updated 26 February 2014