Hairy Crabgrass is a summer annual grassy weed that is also known as Large Crabgrass or by its scientific name, Digitaria sanguinalis. These types of lawn weeds often require a professional application of a select crabgrass killer.
Hairy Crabgrass can be identified as a tufted to horizontally growing summer annual grassy weed that roots at the lower nodes. Its ligule is tall with jagged edges, and its collar is broad and prominent with long hairs at the edges. Hairy Crabgrass also features sheaths that are compressed and flat, with hairy blades that are sharply pointed. Hairy Crabgrass germinates when soil temperatures achieve a consistent 55°F—generally, this lawn weed dies after the first frost.
This grassy weed frequently occurs in various disturbed habitats and in all types of grasses—lawns included. Hairy Crabgrass is commonly found in most parts of the continental United States. These grassy weeds are also summer annuals, meaning they begin to grow (germinate) in the spring, mature in the summer and then produce seeds and die by the fall or first hard frost—an entire life cycle completed within 12 months.
Hairy Crabgrass is a frequent invader of lawns, fields and other landscaping. Once established, good lawn-mowing practices can help prevent it from spreading farther, but may not be enough to stomp this grassy weed out. For effective weed removal, professionally selected and applied weed control treatments are your best bet for eradication.