Although it looks like grass, it is actually a sedge. This means the blades come off the stems in three different directions not two.
Yellow nutsedge is pale green to yellow in color and grows rapidly in the spring and early summer.
It is easy to identify because it grows taller than the rest of the lawn just a few days after mowing. Normally found in wet areas, nutsedge is a good indicator of poor drainage or over watering. But it can be introduced into a well-drained site through contaminated topsoil or plants. Nutsedge is difficult, if not impossible, to control with cultural practices because it produces numerous tubers that give rise to new plants. However, as with many weeds, nutsedge does not grow well in a dense, healthy lawn.