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Carrion flower (Orbea variegata)

Carrion flower forms dense mats in arid regions, preventing native grass and herb seedlings from growing. It can also reduce the growth and health of saltbush when it grows underneath it.

Key facts

Type: Weed, cactus and succulent.

Native to: South-western Africa.

Established in: QLD, NSW, SA.

Other names: star flower, starfish cactus, toad cactus.

Identification

  • It is a leafless, perennial herb and groundcover that grows up to 25 cm tall.
  • Its thick, fleshy stems are 15 to 25 cm long and 1 to 2 cm wide, with serrated edges; they are grey-green or purple-tinged in full sun.
  • Its foul-smelling, five-lobed flowers are 5 to 8 cm wide, cream to yellow with brown or purple markings, and appear from late summer to autumn.
  • Each flower produces a pair of smooth, cylindrical pods about 12 cm long that split open to release fine seeds attached to silky hairs.

Where it grows

In Australia it occurs in arid areas with sandy, well-drained soil, including the North West and Central West of NSW, Queensland, South Australia and Western Australia.

Why it matters

  • Dense mats prevent native grass and herb seedlings from growing.
  • Plants growing beneath saltbush reduce its growth and health.
  • The plant has invaded arid bluebush and saltbush shrublands in Australia.

How it spreads

  • The pods contain many seeds that are easily spread by wind, and the seeds germinate easily.
  • Stem fragments can spread the plant when moved by animals, people dumping garden waste in the bush, machinery or water.

Control options

  • Remove plants early, as small infestations are easier to get rid of.
  • Hand-pull plants and take care to remove the whole plant.
  • Dispose of plant material appropriately to prevent regrowth or spread.
  • Registered herbicides are effective, but the plant may take a while to die; avoid damaging native plants and follow the product label and any permit.

Hygiene and washdown

  • Dispose of plant material appropriately and do not dump garden waste in the bush, as stem fragments can spread the plant.
  • Avoid moving stem fragments on machinery or in water.
  • 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: Regional priority in 1 of 11 regions. Regional priority weed in Central West. 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: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • Western Australia: Permitted, not declared. Listed as a permitted organism in WA, so it can be brought in, but it is not a declared pest.
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Check NT list. There is no NT weed profile for it. Check the NT declared weeds list for its current status.
  • 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)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources