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Cabomba (Cabomba caroliniana)

A submerged aquarium plant that grows into dense underwater stands in dams, lakes and slow rivers. It affects water storages, recreation and aquatic habitat.

Key facts

Type: Weed, aquatic.

Native to: The Americas.

Established in: QLD, NSW, VIC, NT.

Other names: Fanwort.

Identification

  • Submerged plant with finely divided, fan-shaped leaves in opposite pairs along the stem.
  • Small white to pale yellow flowers held just above the water surface.
  • Stems can reach several metres long and break easily.

Where it grows

Still or slow-flowing fresh water up to several metres deep, including water supply storages.

Why it matters

  • Taints and discolours drinking water and blocks off-takes.
  • Makes swimming, boating and fishing dangerous or impossible.
  • Displaces native aquatic plants.

How it spreads

  • Stem fragments moved on boats, trailers, fishing gear and machinery.
  • Aquarium dumping.

Control options

  • Prevention is the main tool: keep it out of new water bodies.
  • Shading, drawdown and harvesting are used in some storages.
  • Herbicide use in water is tightly restricted and needs the right permit.

Hygiene and washdown

  • Check, clean and dry boats, trailers, nets and pumps before moving between water bodies.
  • 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: Sale prohibited; Regional priority in 4 of 11 regions. It must not be imported into NSW or sold anywhere in the state. Regional priority weed in Greater Sydney, Hunter, Murray, North 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: Declared pest (C2), prohibited. C2 Eradication: present in limited areas and targeted for eradication. It must not be brought into WA (prohibited organism).
  • 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 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: Declared pest, notifiable, prohibited. It is a declared pest throughout the ACT. You must report it to ACT Biosecurity. 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)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources