Invasive Species: Potamogeton crispus, Curlyleaf Pondweed
Curlyleaf pondweed is a perennial, submerged, aquatic herb that is native to Eurasia. Leaves are sessile, oblong, stiff, 1.6 to 3.9 in. (4 to 10 cm) long, 0.2 to 0.4 in. (5 to 10 mm) wide, and translucent and have noticeably curly margins (resembling lasagna noodles). Flowering occurs in the summer to early fall, when emergent flowers develop. Flowers are brown, inconspicuous, and wind pollinated. Fruits are flat with a pointed beak and are 0.2 in. (4 to 6 mm) long. In the midsummer, plants form turions (vegetative buds), from which new growth starts in fall or winter. Curlyleaf pondweed tolerates fresh or slightly brackish water and can grow in shallow, deep, still, or flowing water. Plants can grow in clear or turbid water but are mostly shade intolerant. Plants were introduced in the United States, possibly as a hitchhiker on boats, in the mid-1800s.
What are invasive species, and why should we be concerned about them?
Taxonomy: Scientific and Common Names for This Species
Najadales > Potamogetonaceae > Potamogeton crispus L.
Synonym(s): curly-leaved pondweed, curly pondweed
Potamogeton crispus - USDA PLANTS Profile
Distribution Maps
curlyleaf pondweed - The reported distribution of this invasive species across the United States (Source: Invasive Plant Atlas of the United States)
Up-to-the-minute distribution maps and why they are important
Reporting This Invasive Species
What is the best way to report the occurrence of an invasive species?
How to report an invasive species sighting to EDDMapS - Early Detection & Distribution Mapping System
EDDMapS - Report an invasive species to EDDMapS.
County Extension Offices - Find your county Extension office on this map provided by USDA.
How to Identify
This invasive species can be identified by looking for the characteristics described in the paragraphs that follow.
Plant
Curlyleaf pondweed is a perennial, submerged, aquatic herb.
 |
 |
| Chris Evans, River to River CWMA, bugwood.org | Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org |
Foliage
Leaves are sessile, oblong, stiff, 1.6 to 3.9 in. (4 to 10 cm) long, 0.2 to 0.4 in. (5 to 10 mm) wide, and translucent and have noticeably curly margins (resembling lasagna noodles).
|
|
 |
| Leslie J. Mehrhoff, University of Connecticut, bugwood.org | Chris Evans, River to River CWMA, bugwood.org |
Flower
Flowering occurs in the summer to early fall, when emergent flowers develop. Flowers are brown, inconspicuous, and wind pollinated.
| bugwood.org | bugwood.org |
Fruit
Fruits are flat with a pointed beak and are 0.2 in. (4 to 6 mm) long. In the midsummer, plants form turions (vegetative buds), from which new growth starts in fall or winter.
 |
 |
| Leslie J. Mehrhoff, University of Connecticut, bugwood.org | Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org |
Native Species That Resemble Curlyleaf Pondweed
Potamogeton diversifolius, waterthread pondweed - Images at invasive.org
 |
 |
| Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org | Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org |
Potamogeton nodosus, American pondweed - Images at invasive.org
 |
 |
| Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org | Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org |
Additional Images for Curlyleaf Pondweed
curlyleaf pondweed - Images at invasive.org
Learning Resources for Curlyleaf Pondweed
Potamogeton crispus Identification Card - U.S. Fish and Wildlife Service
Potamogeton crispus Fact Sheet - U.S. Fish and Wildlife Service
Additional Information, Biology, Control and Management Resources
Control and management recommendations vary according to individual circumstances. Location, habitat, weather, and a variety of other conditions are factors that help determine the best treatment choice. To find the safest and most effective treatment for your situation, consult your state's land-grant institution. If you will use chemicals as part of the control process, always refer to the product label.
United States Land-Grant University System - Find your Land-Grant University's College of Agriculture, University Cooperative Extension Service, or other related partner on this map provided by USDA.
Fact Sheet - Pennsylvania Department of Conservation and Natural Resources
Invasive Plant Atlas of New England - University of Connecticut
Global Invasive Species Database - Invasive Species Specialist Group
Center for Aquatic and Invasive Plants - University of Florida, Institute of Food and Agricultural Sciences Extension
Nonindigenous Aquatic Species - U.S. Geological Survey (USGS)
Invasive Species - Wisconsin Department of Natural Resources
Plant Profiles - California Invasive Plant Council
Invasive Plants - University of Minnesota Extension
Robert W. Freckmann Herbarium - University of Wisconsin - Stevens Point
Submersed Plants - Washington State Department of Ecology
Bay Grass Identification Key - Maryland Department of Natural Resources
