Curly Pondweed
Potamogeton crispus
Curly pondweed has broad leaves with curly, finely toothed edges. (Photo courtesy Maryland Department of Natural Resources)
(Photo courtesy Maryland Department of Natural Resources)
(Photo courtesy Maryland Department of Natural Resources)
Curly-leaf pondweed is pulled from Otsego Lake by Dr. Bill Harman, Director of the SUNY Oneonta Biological Field Station in Cooperstown, N.Y., on May 22, 2015. The underwater plant is an invasive species in Otsego Lake. (Photo by Will Parson/Chesapeake Bay Program) For noncommercial use contact the Chesapeake Bay Program
Curly pondweed is a bay 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.
Appearance
Curly pondweed is made up of broad leaves with curly, finely toothed edges. These leaves grow to 1 to 4 inches long and 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.
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. It 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. It 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 bay grasses.
- Curly pondweed can be confused with young shoots of redhead grass.
Sources and Additional Information
- Underwater Grasses in Chesapeake Bay & Mid-Atlantic Coastal Waters by Maryland Sea Grant
- Bay Grass Key: Curly Pondweed – Maryland Department of Natural Resources
- Weed Identification Guide: Curly Pondweed – Virginia Tech
- Invasive Plants in Pennsylvania: Curly Pondweed – Pennsylvania Department of Conservation and Natural Resources
- PLANTS Database: Potamogeton crispus – USDA Natural Resources Conservation Service
Quick Facts
Species
Nonnative
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Habitat
Grows in fresh non-tidal to slightly brackish tidal waters.
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Range
Native to Europe; found in the upper Chesapeake Bay and in tributaries such as streams, rivers, lakes and reservoirs throughout the Bay watershed.
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Status
Stable