Spiny Emex

What is spiny emex?

(Emex australis)

Spiny emex plant with fruits, image: Rod Randall, The Plant Protection Society of Western AustraliaGeneric Weed Distribution Map
  • Spiny emex is a weed of pasture and crops.
  • Spiny emex is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of spiny emex are prohibited in Tasmania.

How to identify spiny emex

  • Spiny emex is an annual herb that is usually prostrate (ground-hugging) but which may grow erect when growing among tall plants. Normally a rosette of leaves forms around the crown from which numerous trailing stems develop. Stems are purplish at the base and the leaf nodes, growing to 50 cm long.
  • The leaves are triangular to oval shaped, while the flowers grow in the leaf axils and are small and inconspicuous. Spiny emex fruits go from green to brown as they ripen, are hard and woody, and triangular with three rigid and sharp spines.
  • Seeds germinate at any time but mainly in autumn and winter. Flowering occurs from late winter to early summer. Spiny emex as young as 6 weeks old can produce fruit.
  • For help in identifying spiny emex, search the Dennis Morris Weeds and Endemic Flora database for spiny emex illustrations. If you are still in doubt about the weed you are dealing with, contact your Regional Weed Management Officer on 1300 368 550 for help.
Spiny emex fruit, image Julia Scher
Image top: Spiny emex plant with fruit, photo: Rod Randall, The Plant Protection Society of Western Australia
Image above: Spiny emex fruit, photo: Julia Scher

Spiny emex in Tasmania

  • The distribution of spiny emex is very limited in Tasmania. Spiny emex has been recorded on Flinders Island and occurs near South Arm in the state's south. Spiny emex prefers drier, sandy soils, and occurs as an occasional weed of pastures, roadsides and neglected areas.
  • Spiny emex is a weed of pastures and crops and is toxic to stock. Severe infestations can significantly reduce pasture productivity and crop yields. Although not readily eaten by stock, spiny emex can cause sheep deaths due to poisoning. The spiny fruit can also cause inconvenience to barefooted people, cyclists, and can cripple dogs working in infested areas.

What is the legal status of spiny emex in your area?

Detailed management and control guidelines for spiny emex can be found in the Spiny Emex Control Guide. Refer also to Herbicides for Spiny Emex Control. For further information see DPIPWE's Weed Links and Resources.

See also
Spiny Emex Control Guide
Herbicides for Spiny Emex Control
Statutory Management Plan for Spiny Emex
DPIPWE's Weed Links and Resources

Other useful links
Pest Genie

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