Curly-Leaf Pondweed, known scientifically as Potamogeton crispus, is instantly identifiable by its ruffled, translucent leaves that twist gently along the edges, creating a textured ribbon-like appearance beneath the surface. Often called crisped pondweed, it grows from creeping stems and forms submerged fields in lakes, reservoirs, and slow rivers.

Native to Eurasia, Potamogeton crispus has spread widely and is considered invasive in many regions because it emerges early in the season, well before native plants. It produces specialized overwintering structures called turions, which sink and re-sprout vigorously the following year. This characteristic makes Potamogeton crispus unusually persistent and difficult to control. Dense growth can interfere with recreation, shade native species, and alter water clarity, yet its distinctive crinkled leaves make it one of the most recognizable pondweeds.