Creeping Knapweed

(Acroptilon repens)

Creeping Knapweed1

Status of creeping knapweed in Tasmania

  • Creeping knapweed is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of creeping knapweed are prohibited in Tasmania.
  • The legal responsibilities of landholders and other stakeholders in dealing with creeping knapweed are laid out in the Creeping Knapweed Statutory Weed Management Plan.

What does creeping knapweed look like?

  • Creeping knapweed is an erect, perennial (long-lived) herb growing from 40 to 100 cm high. The stems are covered with dense soft grey hairs, while the leaves are silvery to greyish green and slightly hairy. The rosette leaves (leaves in a whorl close to the ground) are shortly stalked, lobed and toothed, while the stem leaves are only slightly toothed or entire and have no stalks. The flower-heads are urn-shaped, made up of numerous purple, lilac or pink tubular florets, and are born singly on the ends of branches. Creeping knapweed has an extensive and rapid-growing, woody root system which gives rise to dense colonies with many aerial shoots.
  • Seeds germinate during winter and summer. Creeping knapweed remains as a rosette in its first summer, dies back in autumn, and then produces new growth and flowers in the following spring and summer.
  • Creeping knapweed produces large numbers of seeds although seedlings are rare. Seed can be spread in contaminated hay and other seed. Creeping knapweed also spreads via root fragments being transported by cultivation equipment.
Creeping Knapweed1 Creeping Knapweed3
Image top: creeping knapweed flowers, © CDFA.
Image above left: creeping knapweed flower, © Neal Kramer.
Image above right: creeping knapweed, © CDFA.

Impacts of creeping knapweed

  • Creeping knapweed is a weed of irrigated crops and cereals, and heavy infestations of creeping knapweed can greatly reduce crop yields. Creeping knapweed is thought to be able to grow in a number of areas of Tasmania, and has the potential to be a very serious agricultural weed in Tasmania.

Where does creeping knapweed occur?

  • Creeping knapweed originates from the Caspian Sea region, Asia Minor, Afghanistan, and Mongolia.
  • Creeping knapweed has established widely on mainland Australia in New South Wales, Victoria, Queensland and South Australia.
  • Creeping knapweed has not managed to establish in Tasmania. However it has occasionally been found as a contaminant of imported animal feed grain.

What you need to do

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

See also
Creeping Knapweed Statutory Weed Management Plan
Weed Links and Resources

Other useful links
Pest Genie

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