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Parkinsonia (Parkinsonia aculeata)

A thorny small tree that forms thickets along watercourses and floodplains across northern Australia, with seed spread far by floodwater.

Key facts

Type: Weed, tree.

Native to: Tropical America.

Established in: QLD, WA, NT.

Other names: Jerusalem thorn.

Identification

  • Shrub or tree to 8 m with smooth green bark and sharp spines at the leaf bases.
  • Long, flattened leaf stalks with tiny leaflets, giving a weeping look.
  • Yellow flowers with one orange-spotted petal and light brown pods constricted between seeds.

Where it grows

Wetlands, watercourses, floodplains and bore drains in the tropics and arid zone.

Why it matters

  • Thickets restrict access to water and mustering.
  • Degrades wetlands and riparian habitat.

How it spreads

  • Floating pods and seed carried by floodwater.
  • Seed in mud on vehicles and stock.

Control options

  • Basal bark, cut stump or soil-applied registered herbicides.
  • Mechanical removal and fire followed by regrowth control.
  • Several biological control agents have been released.

Hygiene and washdown

  • Clean mud from vehicles after working along infested creeks and drains.
  • 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): Weed of National Significance. One of 32 nationally agreed priority weeds, managed through national strategies with all states and territories.
  • Queensland: Restricted matter, category 3. Do not give it away, sell or release it into the environment. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Control order; Sale prohibited. A state control order applies, so follow its eradication and reporting requirements. It must not be imported into NSW or sold anywhere in the state. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Restricted weed. Where it is a restricted weed, trade in it (including the plant, its seed or contaminated material) is prohibited.
  • 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: Declared pest (C3). C3 Management: landholders must manage it to reduce its impact and stop it spreading.
  • Tasmania: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • Northern Territory: Declared weed, Class B. Class B: growth and spread must be controlled. All declared weeds are also Class C, so they must not be brought into the NT.
  • Australian Capital Territory: Declared pest, prohibited. It is a declared pest throughout the ACT. Dealing with it, such as selling, moving or keeping it, is prohibited.

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)
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA 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