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Curly-leaf pondweed

Quick facts

Curly-leaf pondweed is a prohibited invasive species. It is illegal to possess, import, purchase, transport, or introduce these species (including hybrids or cultivars) except under a permit or statutory exemption. Transport directly to the Minnesota Department of Natural Resources in a sealed container for identification or reporting purposes is permitted.

  • Curly-leaf pondweed winter buds (turions) sprout under the ice in late fall and early winter, allowing them to grow rapidly in the spring before native plant species are active.
  • Dense surface mats can reduce light penetration and impede recreational activity.

Curly-leaf pondweed should be reported. See the Minnesota Department of Natural Resources recommendations for reporting invasive species.

How to identify curly-leaf pondweed

Potamogeton crispus

  • Submerged aquatic plant with lasagna-shaped leaves that can form dense mats at the water’s surface.
  • Typically grows in waters up to 15 feet deep.

Leaves

  • Simple, alternate leaves that are typically up to 3 inches long with a serrated margin and wavy edges.
  • Leaves have an obvious midvein and rounded tips.
  • Produces winter buds (called “turions”) at leaf axils with densely packed leaves that may resemble small pine cones.

Flowers

  • Grow on short spikes about 1 inch tall, above the water.
  • Flowers may appear reddish-brown to green.

Roots

  • Vegetative reproduction via thick yellow to red rhizomes.
Winter buds (turions) at leaf axils
Leaves with a serrated margin and wavy edges

Angela Gupta, Extension educator; Amy Rager, Extension educator; Megan M. Weber, Extension educator

Reviewed in 2019

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