Nut grass has solid stems that are triangular in cross section. The leaves grow from the base in groups of three. It will thrive in water logged soil. There are two types, yellow and purple, identified by the flowering stem. Nut grass spreads rapidly. Remove when they are young by digging or pulling and cover the area with layers of landscape fabric or cardboard. Top with chipped bark and leave the cover in place for at least one growing season. An easier method would be to treat with Sedgehammer, which can be purchased at our nursery.