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Devil's claw (Martynia annua)

Devil's Claw invades disturbed sites in northern Australia, where it can prevent native plants from regenerating. Its hard, hooked fruits can injure livestock and may carry seeds on animals, machinery and vehicles.

Key facts

Type: Weed, herb.

Native to: Mexico, Central and South America, and some Caribbean islands.

Established in: QLD, NSW, NT.

Other names: Small-fruit Devil's Claw, Small-fruited Devil's Claw, Iceplant, Tiger's Claw.

Best time to act: Look for seedlings mainly during the wet summer period from October to March, and treat plants before they flower and seed, usually from December to March.

Identification

  • An upright annual herb, 0.25 to 2 metres tall, with much-branched greenish stems covered in glandular hairs that produce sticky sap.
  • Its kidney-shaped to nearly circular leaves grow up to 12.5 centimetres across and have five to seven shallow lobes.
  • Pink, lavender or white tubular, bell-shaped flowers are 3 to 5 centimetres long and grow in clusters near branch tips; they have darker purple petal markings and yellow and red markings in the throat.
  • The fleshy fruit is 2 to 3 centimetres long and contains two large seeds; as it matures, it hardens from green to grey or black and splits into two claws, 5 to 10 millimetres long.
  • The seeds are brown to black, oblong and somewhat flattened.
  • Look-alike: Purpleflower Devil's Claw (Proboscidea louisiana) has larger fruits, 8 to 30 centimetres long, with claws longer than the capsule.
  • Look-alike: Yellowflower Devil's Claw (Ibicella lutea) has larger fruits, 10 to 25 centimetres long, claws longer than the capsule, and denser flower clusters.

Where it grows

In Australia it occurs in coastal and subcoastal parts of the Northern Territory, north-east and central Queensland, and north-east New South Wales, especially in disturbed places such as stockyards, roadsides, pastures and crops.

Why it matters

  • It invades disturbed sites and can prevent the regeneration of native species.
  • The plant is not considered palatable to stock, so grazing does not limit its survival and spread.
  • Its hooked fruits can attach to animals and work into soft parts such as the skin, mouth and hooves, causing injury.
  • It could potentially harbour serious insect pests of North Queensland tobacco crops.

How it spreads

  • It spreads predominantly by seeds that remain inside the pods.
  • The clawed pods can attach to passing animals, farm machinery and vehicles.

Control options

  • Before flowering, remove plants by hand, cultivation or hoeing; small infestations can also be slashed close to the ground.
  • Regrowth may occur if plants are too young or are slashed too high; the species is known to reproduce by seed and does not resprout from the roots.
  • Larger colonies can be treated by spot-spraying or boom-spraying with registered herbicides; consult the Australian Pesticides and Veterinary Medicines Authority for chemical information.

Hygiene and washdown

  • Check and clean vehicles and farm machinery to remove hooked fruits before moving between sites, as the pods can attach to them and carry seeds.
  • 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: Declared pest (C1), prohibited. C1 Exclusion: to be kept out of WA, or out of the parts of WA where it is not established. Report any sighting to DPIRD. It must not be brought into WA (prohibited organism).
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Declared weed, Class A. Class A: to be eradicated. All declared weeds are also Class C, so they must not be brought into the NT.
  • 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
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources