Nut grass grows on lawns throughout the country. It is most visible on freshly mowed lawns. Both yellow and purple nut grass are green with yellow tints. Both types resemble regular grass in texture.
Despite its name, nut grass is a weed, not a grass. It produces tubers, not nuts. A tuber is a bulb-like formation that stores food for the plant during winter months. The proper name for nut grass is nut sedge. Unlike grasses that have round stems, sedges have triangular stems that thrive on water.
The purple variety of nut grass (Cyperus rotundus) generates more tubers than the yellow (Cyperus esculentus) and has wide leaf tips. Yellow nut grass leaves are very slender at the ends. The latter type is easier to control.
Causes and Eradication
Considering its thirst for moisture, nut grass is most likely to grow on poorly drained lawns. Another common cause for the growth of the annoying weed is applying overly moist topsoil on a lawn. The weeds can be pulled or eliminated with commercially available herbicides or pesticides.