Control of Canadian Pondweed

Canadian pondweed, photo: Kiowa Fenner 


  • Plan your control program, this will save time and money in the long-run;
  • Consider the impact of your control methods on off-target species, especially if herbicides are used;
  • Get in early - For new infestations, eradicate before the plants reach the flowering stage: once plants begin seeding, control becomes more difficult and expensive;
  • Carefully time your use of herbicide for best results (see the Herbicides for aquatic weed control link for more information);
  • Coordinate your control program with neighbouring landholders where your weed problem crosses property boundaries;
  • Revisit and regularly inspect the site and ensure follow-up is undertaken.


  • Don't start your control program without first planning your approach;
  • Don't allow an infestation to become established. Get in early!
  • Don't rely on just one treatment: follow-up is essential.

Spread of Canadian pondweed

  • Only male plants occur in Australia, and all reproduction is vegetative. Infestations of Canadian pondweed increase in size when the over-wintering colony begins new growth in spring.
  • New colonies are formed when stem fragments break away from the colony in stream flow and establish downstream. Canadian pondweed stems break easily when disturbed mechanically, and in late summer and autumn large numbers of stem fragments are swept along irrigation channels to take root downstream.

Physical removal

  • Hand pulling, cutting and the use of booms and draglines can provide temporary relief, but are expensive and time-consuming and are not effective in the long-term control of Canadian pondweed.
  • Physical removal provides only temporary reduction of an infestation, and can encourage spread of the weed by stem fragments.

Lowering water levels

  • Lowering water levels in an infested water body or channel can be effective in controlling Canadian pondweed provided the site is completely drained, preferably in summer, exposing the weed to drying out.

Chemical control

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