What does it look like?
Curled pondweed is a submerged aquatic plant with green to reddish‑brown leaves arranged alternately along thin stems rooted in bottom sediments. The leaves are narrow (around 10 mm wide and up to 8cm long), stalkless, and have distinctive wavy, finely toothed edges, which gives the plant its name. Each leaf has three main veins that are usually reddish.
Small green flowers are produced above the water surface from November to January, forming short spikes up to about 1 cm long. Curled pondweed is found in lakes, ponds, rivers, streams and drains.
It spreads through rhizomes, seeds, stem fragments and turions (hardened buds), allowing it to establish and spread quickly once present.
Why is it a problem?
Curled pondweed can form dense stands that outcompete native plants, suppress regeneration and change habitat structure. Once established, it’s very difficult to control and usually requires a specialist aquatic pest plant control operator.
Curled pondweed can be confused with native pondweeds. Potamogeton ochreatus and P. cheesemanii. P. ochreatus has straight‑edged leaves with a blunt tip, while curled pondweed has a rounded leaf tip and distinctive crimped edges. It can be distinguished from P. cheesemanii by its narrower, more tightly crimped submerged leaves.
Control methods
Please contact our biosecurity team to discuss control options on 06 835 9200.
More information
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by Department of Conservation (DOC). 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by DOC.
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