Curly Pondweed
Potamogeton crispus

Curly pondweed is a non-native underwater grass with broad, curly leaves along flat, branched stems. It grows in fresh, non-tidal to slightly brackish tidal waters throughout the Chesapeake Bay watershed.

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A hand holds four reddish-brown curly pondweed leaves, no larger than the hand's palm.
Curly-leaf pondweed is an invasive species that is native to Eurasia, Australia and Africa but spread to North America via the aquarium trade. (Photo by Will Parson/Chesapeake Bay Program)

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Appearance

Curly pondweed is made up of broad leaves with curly, finely toothed edges. These leaves grow to 1 to 4 inches long. They grow alternately or slightly opposite on flat, branched stems.

In winter, leaves are blue-green and more flattened. In spring and summer, leaves are reddish-brown and become wider and curlier. Curly pondweed has a shallow root and rhizome system which is a type of plant stem with nodes that roots grow from.

Reproduction and life cycle

Curly pondweed has a three-stage life cycle. During spring and summer, flowers bloom and float at the water’s surface. The plant begins to die in mid-summer after producing buds, which lie dormant until autumn. In winter, the spring/summer cycle repeats itself when buds sprout into new flowers. Curly pondweed can also reproduce asexually when rhizomes or burr-like structures near the tips of the stems develop into new plants.

Did you know?

  • Curly pondweed was likely introduced to the United States in the mid-1800s.
  • It can become invasive in non-tidal waters because it grows early in the season and can shade out other underwater grasses.
  • Curly pondweed can be confused with young shoots of redhead grass.

Sources and additional information

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