Bottle brush sedge is a clump-forming plant with large tufts of lime-green leaves and flowering stalks. The flowering stalks consist of a single male spikelet and numerous female spikelets. The nodding female spikelets look bristly like a bottle brush, hence its common name. These spikelets start out green and then mature to a deep brown by August as the seed ripens. Waterfowl eat the seeds. Bottle brush sedge is an obligate wetland species and tolerates deeper water than most sedge species.