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Sword pear (Acanthocereus tetragonus)

Sword pear can spread and cover large areas, reducing land productivity and affecting the environment. Its sharp spines can injure people and animals.

Key facts

Type: Weed, cactus and succulent.

Native to: Florida, the Caribbean and Mexico through Central America to northern South America.

Established in: QLD.

Other names: Barbed-wire Cactus, Triangle Cactus.

Identification

  • It is a shrub cactus with erect or clambering stems 1–5 m long, often arching and rooting at the tips.
  • Stems are 3–8 cm in diameter and usually have three prominent angles, though some have four or five, with coarsely wavy margins.
  • Areoles have 4–7 radial spines, rarely up to 12, which are 1–5 cm long, and one or two longer central spines.
  • Its white, trumpet-like flowers are 15–25 cm long and open at night.
  • Red fruits are 3–8 cm long and 2.5–7 cm in diameter; they may be naked or spiny and contain numerous black, smooth, shiny seeds.
  • Look-alike: Harrisia cactus has a similar form, but its stems have 4–6 angles and one to several long spines with smaller radial spines.
  • Look-alike: Night-blooming cactus has 1–4 small spines per areole and larger fruits with fleshy scales; Tiger Pear has short, rounded, detachable stem segments and small yellow flowers.

Where it grows

In Queensland, sword pear occurs in wooded country around Gogango, including disturbed Brigalow forests on clay soils and river-flat forest on sandy soil near Rockhampton.

Why it matters

  • Birds and animals eat the succulent fruits and distribute seeds in their droppings, assisting the plant's spread.
  • The species has the potential to spread and cover large areas, affecting the environment and reducing land productivity.
  • Its sharp spines are a hazard to people and animals.

How it spreads

  • Sword pear reproduces by seed and by fragments of its fleshy stem segments.
  • Birds and animals spread seeds after eating the fruit.
  • Animals or discarded garden waste may spread small stem fragments.

Control options

  • Use registered herbicides in accordance with relevant requirements.
  • Cut small infestations and single plants off at or below ground level.
  • Notify your local weed management authority if you see this species.

Hygiene and washdown

  • Do not move stem fragments or discard cactus material as garden waste, as fragments can spread the plant.
  • 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: 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)

Sources