Cotton Sedge or Cotton Grass grows to 36 inches tall and is found in marshlands and grows in full sun to part shade and multiplies by rhizomes. The green grass stems produce brown-green flowers that give way to stiff white seed heads that resemble cotton. Cotton Sedge adds texture and interest all season long. Grows well in 2 inches of water in bogs or naturalized in wetlands and is great on stream or river banks to help avoid soil erosion. Prefers moist, acidic soil and grows in part sun to part shade. Once used as an edible herb and for cooking, this grass grows to 12 - 36 inches tall with division by root and propagates by seed. Cotton Sedge is a perennial plant that is cold hardy and native to Northern Europe and North America.