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Woolly cockspur (Centaurea eriophora)

Woolly cockspur is an introduced annual herb that can establish in disturbed areas and compete with pasture plants and native vegetation. Its woolly, spiny flower heads can make infested areas difficult to handle and may contaminate wool or other produce.

Key facts

Type: Weed, herb.

Native to: Mediterranean region.

Established in: SA.

Other names: Woolly star-thistle, Woolly centaury.

Best time to act: Look for plants during active growth and treat them before flowering heads mature and release seed.

Identification

  • It is an erect, branching annual herb with stems and leaves covered in dense, pale woolly hairs.
  • Leaves are alternate; lower leaves are often divided into lobes, while upper leaves are narrower and less divided.
  • Rounded flower heads occur at the ends of branches and are conspicuously woolly.
  • The heads bear yellow florets and stiff, sharp-pointed involucral bracts.
  • Look-alike: Other spiny Centaurea species, including yellow star-thistle, may look similar; the dense woolly covering of the flower heads is a useful feature to check.

Where it grows

In Australia it can grow in disturbed ground, roadsides, pasture and other open sites.

Why it matters

  • It can compete with desirable pasture plants and native vegetation, particularly where the ground is disturbed.
  • Sharp bracts can make dense infestations difficult for people and stock to move through.
  • The spiny heads may contaminate wool or other harvested material.

How it spreads

  • It reproduces by seed, which can be moved in or on contaminated soil, machinery, vehicles and equipment.
  • Seeds or seed heads may also be carried by animals, including in wool or fur, and in contaminated fodder.

Control options

  • For small infestations, hand-pull or dig out plants before they set seed; wear gloves and handle the spiny heads carefully.
  • Where appropriate, use a herbicide registered for the site and target plant, following the product label and relevant local advice.
  • Treat plants before seed maturation and revisit the site to control new seedlings and any missed plants.
  • If the plant is newly found or suspected in your area, check with the state or territory biosecurity agency about reporting.

Hygiene and washdown

  • Clean soil, plant material and seed heads from boots, clothing, vehicles and machinery before leaving an infested site.
  • Avoid moving contaminated soil or fodder, and dispose of collected seed heads so they cannot spread.
  • Inspect and clean vehicles, plant and footwear before leaving an infested area, paying attention to tyres, radiators, belly plates, tracks and floor mats.
  • Wash down at a designated bay where runoff is contained and can be monitored for seedlings.
  • Record each washdown so the client has evidence of clean entry and exit.

Classification by state

  • Australia (national): No national listing. Managed under state and territory law.
  • Queensland: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Not a priority weed. Not a state or regional priority weed in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • Tasmania: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • Northern Territory: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources