African Thistle

African thistle, photo: Department of Agriculture and Food, Western Australia

Status of African thistle in Tasmania

(Berkheya rigida)
  • African thistle is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of African thistle are prohibited in Tasmania.
  • The legal responsibilities of landholders and other stakeholders in dealing with African thistle are laid out in the African Thistle Statutory Weed Management Plan.

What does African thistle look like?

African thistle is a herbaceous to woody perennial (long-lived) herb growing from 30 to 80 cm high. The stems can be upright or spreading and are conspicuously wooly at the base. Stems can form roots where they touch the soil. The leaves are wooly on the underside, stiff, with deeply cut and spiny lobes. The flower head is made up of many yellow tubular florets grouped into small terminal heads. The short thick rootstock produces an extensive mat of roots and rhizomes (underground stems) in the surface soil layer.

Seeds germinate in autumn and young plants form a rosette of leaves. Flowering occurs in late spring through summer. The above-ground growth dies off in late summer and early autumn, with new growth developing from the crown and rhizomes in late autumn.

African thistle is spread when the spiny flower-head forms a burr which is picked up and carried by passing animals. Seeds fall from the burr as it is carried or rolled along. Colonies increase in area through rhizome growth and stem layering.

African thistle
Flowering African thistle, photo: Department of Agriculture and Food, Western Australia
African Thistle
copyright: V. Tyrer

African Thistle, flowering plant, photo: V. Tyrer
African Thistle

Images above (left t right): African thistle; flowering plant, photo: V. Tyrer
copyright:
V. Tyrer

Impacts of African thistle

  • African thistle is unpalatable and dense infestations can reduce pasture productivity and prevent access to beaches and recreational areas. There is the potential for African thistle to spread widely in Tasmania in coastal and inland areas.

Where does African thistle occur?

  • African thistle is native to South Africa. African thistle occurs at several ports in Western Australia, South Australia and Victoria, probably as a result of seed being dumped in ballast water.

  • African thistle established a population King Island, but has since been eradicated. African thistle has not naturalised elsewhere Tasmania.


What you need to do

  • If you locate African thistle anywhere in Tasmania, or if you find a plant that you think could be African thistle, immediately contact your Regional Weed Management Officer on 1300 368 550 to report this weed.
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    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.

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