Includes: Bolivian wattle, white ball acacia (Acaciella angustissima formerly Acacia boliviana), camel thorn, giraffe thorn (Acacia erioloba), cutch tree (Acacia catechu), fever tree (Acacia xanthophloea), karroo thorn (Vachellia karroo formerly Acacia karroo), prickly acacia (Vachellia nilotica formerly Acacia nilotica), red thorn (Acacia gerrardii), soap nut (Acacia sinuata) and umbrella tree (Acacia tortilis).
Form: tree/shrub - perennial
Status: present in WA
Trees and shrubs sometimes spiny. One species, prickly acacia (Acacia nilotica) is a Weed of National Significance (WoNS).
Leaves: bipinnate, that is they are divided twice and give a feathery appearance.
Flowers: grouped into dense globular or cylindrical spikes, either in the axils of the leaves or at the end of branches.
Thorns: non-native acacia can be distinguished from native acacia by their large thorns.
Online weed identification training
Login or set up a new account on DAFWAs online training site to access:
- a training course on how to identify African acacias and report them.
- training material that you can use to teach community groups how to identify African acacias.
Agricultural and economic impact
Acacias can be very invasive. For example, karroo thorn acacia could potentially invade large areas of South West, Western Australia. It can form dense thorny thickets reducing agricultural productivity and loss of native habitat.
Declared pest category
The Western Australian Organism List (WAOL) contains information on the area(s) in which this pest is declared and the control and keeping categories to which it has been assigned in Western Australia (WA). Search for Acacia species in the WAOL using the scientific name Acacia. Each Acacia species in WAOL has a declaration and declaration map.
Requirements for land owners/occupiers and other persons
Requirements for land owners/occupiers and other persons if this pest is found can be sourced through the declared plant requirements link.
Weed of national significance
Prickly acacias have been prioritised at a national level as Weeds of National Significance (WoNS). Further details on Weeds of National Significance can be found by visiting the external link(s) on this page.
Search > detect > report
Detectability: medium difficulty to find. Karroo thorn is a tree with yellow flowers, similar to Australian wattles. Its most distinctive feature is large pale thorns growing along the younger stems in V-shaped pairs – these thorns can be up to 100 millimetres long. Karroo thorn could be confused with some thorny garden trees that are not declared, but these have red or brown thorns. Any other tree with long pale thorns in pairs is likely to be other exotic Vachellia or Acacia species. All exotic Vachellia and Acacia species should be reported.
Who should look for it: potentially anyone in the South West Land Division could find karroo thorn including biosecurity groups, local governments, general public, home gardeners, farmers, permaculturists, the nursery industry and any horticultural professionals.
When to find it: karroo thorn could be found at any time of year.
Where to find it: karroo thorn is most likely to be found in cultivation. Karroo thorn and similar species have previously been found in several Australian States in home gardens, botanic gardens and zoos.
Report the presence of any acacia with thorns before undertaking a control measure. Control methods for this declared plant can be found on DAFWA's acacia control web page.