Marshes, shores, swales, bogs, wet prairies and meadows, and moist places generally; thickets and openings along streams; a major wetland dominant in much of the state. Rarely in more upland settings near Lake Superior.

A rather variable species, sometimes confused with the others, especially C. stricta subsp. inexpansa, but distinguishable once one is familiar with the very thin texture of the lemma. The sheaths may be either glabrous or pubescent.