Yellow nutsedge is a grasslike perennial sedge with triangular stems and ¼-inch-wide leaves. Also called yellow nutgrass, it reproduces by seed and tubers that grow at the root tips. Tubers often persist in the soil, making established plants difficult to control.
Mow high in early to midsummer and water infrequently though thoroughly. Spot-treat with postemergence herbicides labeled for nutsedge. As with most weeds, control is easiest when plants are small.