Curly Pondweed Potamogeton crispus LinnaeusNon-native  -  Invasive  


Curly Pondweed is found in a variety of different aquatic habitats. From Deep Creek Lake in Garrett County to the streams of the piedmont and the coastal plain creeks of the Eastern Shore, Curly Pondweed has become established many of Maryland's waterways. Curly Pondweed's native distribution is throughout most of Eurasia, Africa, and Australia. It became established in the United States in the early 1800's. According to the USGS Nonindigenous Aquatic Species website, the first collection of Curly Pondweed was in the Philadelphia area in 1841. By the early 1980's Curly Pondweed was found throughout most of the United States and Canada.


From the USGS Nonindigenous Aquatic Species website: Curly Pondweed grows entirely as a submersed aquatic plant with no floating leaves. Leaves are alternate, 4-10 cm in length and 5-10 mm wide. Leaves are conspicuously toothed along leaf margins, sessile (attached directly to the stem), narrowly oblong, undulate (wavy like lasagna noodles) with a conspicuous mid-vein. Leaf tips are obtuse (rounded or blunt), olive-green to reddish-brown, and somewhat translucent. Stems are flattened, channeled, with few branches. Rhizomes are pale yellow or reddish, rooting at the nodes. Small flowers (3 mm wide), with greenish-brown or greenish-red sepals form on a terminal spike above the waterline producing 3-4 achenes (fruits) per flower.

Where to find:

Look for this invasive plant in any of Maryland's many waterways.

There are 22 records in the project database.

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Curly Pondweed in Garrett Co., Maryland (7/22/2015). Photo by Seth Metheny. (MBP list)

Curly Pondweed in Baltimore Co., Maryland (11/5/2016). Photo by John Hall. (MBP list)

Curly Pondweed in Cecil Co., Maryland (6/26/2016). Photo by Jim Brighton. (MBP list)

Curly Pondweed in Garrett Co., Maryland (9/23/2015). Photo by Seth Metheny. (MBP list)

Curly Pondweed in Howard Co., Maryland (6/26/2017). Verified by Dr. John Hall. Photo by Sue Muller. (MBP list)

Curly Pondweed in Anne Arundel Co., Maryland (7/8/2011). Verified by John D. Hall, Norton-Brown Herbarium. Photo by Bill Harms. (MBP list)

Curly Pondweed along the Little Patuxent River in Howard Co., Maryland (7/26/2017). Photo by Sue Muller. (MBP list)

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