There are two common types of crabgrass--hairy crabgrass (Digitaria sanguinalis) and smooth crabgrass (D. Ischaemum). It doesn't make too much difference which one is present. They look similar and are similar in control. One has hairs on the leaf and the other doesn't. They are both annuals and germinate sometime in May. They are both coarse, unsightly grasses and can grow close to the ground and thus escape the mower. Prolific seed producers. The crabgrass rake can be used to control lighter populations.
Photo by Dr. John Meade, weed scientist emeritus
Rutgers NJAES Cooperative Extension