Sedge is a type of grass-like plant that grows in wet places like marshes, swamps, and along the edges of ponds and streams. If you've ever walked near a lake and noticed tall, narrow plants with triangular stems growing in clumps at the water's edge, you were probably looking at sedge.

Sedges look similar to regular grasses, but there's a trick to tell them apart: sedge stems are solid and triangular (with three sides), while grass stems are round and hollow. If you gently roll a sedge stem between your fingers, you can feel the corners. People sometimes remember this with the saying “sedges have edges.”

These plants play an important role in nature. Their dense root systems help hold soil in place along riverbanks and prevent erosion. Ducks and other waterfowl use sedge for building nests, and the seeds provide food for birds. Some sedges grow in such thick patches that they create natural filters, cleaning water as it flows through them.

Some types of sedge have leaf edges sharp enough to give you a paper-cut-like scratch if you're not careful when handling them.