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Fine-bristled burrgrass (Cenchrus brownii)

It is mostly an agricultural weed, but also occurs on beaches and in coastal habitats. In Australia it is found on offshore Western Australian islands, in the Torres Strait and on the Northern Territory mainland, and its burrs can spread on clothing or animals.

Key facts

Type: Weed, grass.

Native to: Tropical America.

Established in: QLD, NT.

Other names: Brown’s Burgrass, Brown’s Sandbur, Burr-grass, Fine-Bristle Sandbur.

Best time to act: It flowers from April to June.

Identification

  • It is an upright to straggling annual grass, with stems that start horizontal and may root where leaves form before growing upright.
  • Stems grow to 25–110 cm high, and leaf-blades are 8–40 cm long and 4–13 mm wide.
  • Green flower clusters are 3–12 cm long and about 1.5 cm wide, with many crowded burrs.
  • Each burr is 3.5–4 mm wide, with slender barbed bristles around a rigid cup and inter-crossing spines.
  • The egg-shaped seed is 1.9–2.6 mm long and is shed enclosed in the burr.

Where it grows

In Australia it grows in disturbed places, particularly near the ocean and on limestone soils, and is recorded on offshore Western Australian islands, in the Torres Strait and on the Northern Territory mainland.

Why it matters

  • It is mostly an agricultural weed.
  • It also occurs on beaches and in coastal habitats.

How it spreads

  • It disperses by seed, and its burrs detach easily from the flower spike.
  • The burrs attach to clothing or animals.

Control options

  • Specific control methods for fine-bristled burrgrass are not known.
  • Other Cenchrus species are controlled by physical or chemical means.
  • It also recommends observing machinery hygiene protocols and not buying stock from infested areas.

Hygiene and washdown

  • Follow machinery hygiene protocols; the burrs detach easily and can attach to clothing or animals.
  • 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: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • 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.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources