Cenchrus longispinus (innocent weed) and Cenchrus incertus (spiny burrgrass)

Status of burrgrass in Tasmania

Spiny burrgrass 

The two species of spiny burrgrass, C. longispinus (innocent weed), and C. incertus (spiny burrgrass), are declared weeds in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of spiny burrgrass are prohibited in Tasmania.

The legal responsibilities of landholders and other stakeholders in dealing with spiny burrgrass are laid out in the Cenchrus longispinus (Innocent Weed) Statutory Weed Management Plan and the Cenchrus incertus (Spiny Burrgrass) Statutory Weed Management Plan.

What does burrgrass look like?

  • The two species of burrgrass (C. longispinus and C. incertus) are similar in appearance. They are erect or spreading annual (C. longispinus) or perennial (C. incertus) grasses growing to 60 cm high. Several branched and somewhat flattened stems are produced from the base. The leaves grow to 20 cm long and 5 to 8 cm wide, are sometimes twisted and wrinkled, and are finely serrated. The flowers are borne in spike-like flower heads, with each flower head containing up to 40 spiny burrs containing the seeds.
  • Seeds can germinate any time of year except mid-winter, most germination occurring in spring and early summer. The burrs are produced from December to April. Most C. longispinus plants die in autumn or early winter, while C. incertus may regrow from a crown each spring and act as a perennial.
  • Spread is by seed contained in the spiny burrs. The burrs adhere to wool, fur and clothing, as well as vehicle tyres and other machinery. Burrs can also be spread in water and contaminated hay.

Spiny burrgrass 2 Spiny burrgrass 3 Innocent Weed
Images top, above left & centre: spiny burrgrass, © Steve Matson
Image above right: innocent weed

Impacts of burrgrass

  • Burrgrass is a serious weed due to its burrs. These become tangled in wool and cause damage to the fleece. The burrs can also puncture the skin of animals and cause damage to hides, as well as cause ulcers in the mouths of grazing animals.

Where does burrgrass occur?

  • Burrgrass is a native to North and Central America. Burrgrass has naturalised widely on mainland Australia.
  • Spiny burrgrass has not managed to establish in Tasmania.

What you need to do

If you locate Burrgrass anywhere in Tasmania, or if you find a plant that you think could be burrgrass, immediately contact Biosecurity Tasmania on 03 6165 3777 to report this weed.

See also
Cenchrus longispinus (Innocent Weed) Statutory Weed Management Plan
Cenchrus incertus (Spiny Burrgrass) Statutory Weed Management Plan
Weed Links and Resources

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

Important Disclaimer
To the extent permitted by law, the Tasmanian Department of Primary Industries, Parks, Water and Environment (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using information or material (in part or in whole) contained on this website.