Curly leaf pondweed

Potamogeton crispus

By the Minnesota State DNR’s definition,

“Curly leaf pondweed is an exotic plant that forms surface mats that interfere with aquatic recreation. The plant usually drops to the lake bottom by early July. Curly-leaf pondweed was the most severe nuisance aquatic plant in the Midwest until Eurasian watermilfoil appeared. It was accidentally introduced along with the common carp.”

MN DNR’s Fact Sheet on Curlyleaf Pondweed

Curlyleaf pondweed on the MN DNR Website