Floating Water Chestnut

(Trapa species)

Floating water chestnut - nut

Status of floating water chestnut in Tasmania

  • Floating water chestnut is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of floating water chestnut are prohibited in Tasmania.
  • The legal responsibilities of landholders and other stakeholders in dealing with water hyacinth are laid out in the water hyacinth Statutory Weed Management Plan.

What does floating water chestnut look like?

  • Floating water chestnut is an aquatic weed of ponds, freshwater estuaries and mudflats.
  • European water chestnut (T. natans) forms a rosette of leaves arising from the tip of a long (1 to 1.5 m) submerged stem. The leaves are waxy, triangular and with toothed margins. The flowers are inconspicuous, four-petalled, white and located in the centre of the rosette. The fruit is a distinctive four-horned nut containing a single seed.
  • Floating water chestnut spreads by seed.

Floating water chestnut - leaves 

Image top left: floating water chestnut - nut.
Image above: floating water chestnut - leaves.

Impacts of floating water chestnut

  • Floating water chestnut is a serious weed of freshwater water bodies.

Where does floating water chestnut occur

  • Floating water chestnut is a native of warm temperate southern Europe and Asia.
  • Floating water chestnut has not established anywhere in Australia.

What you need to do

  • If you locate floating water chestnut anywhere in Tasmania, or if you find a plant that you think could be floating water chestnut, immediately contact Biosecurity Tasmania on 03 6165 3777 to report this weed.
See also
Weed Links and Resources

Other useful links
Pest Genie

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