Crabgrass

Smooth crabgrass and large crabgrass

Digitaria ischaemum and D. sanguinalis

 

Weed Type: Grass
Life Cycle: Summer annual

 

Both types of crabgrass reproduce primarily by seeds. Large crabgrass can also reproduce by long, rooting tillers.

Both crabgrasses are much-branched and upright or prostrate. Large crabgrass is normally mat forming, often has purple stems, and can grow to more than 3 feet in height. Smooth crabgrass is usually 15 inches or less.

 

Both crabgrasses can be found in most warm, moist, fertile lawns in sun where turf is thin or mowed too short. They will tolerate hot, dry, compacted soils after establishment, and may spread aggressively to crowd out desirable grasses.

 

To control without chemicals maintain turf density and health through proper culture; avoid light, frequent irrigation, spring cultivation, short mowing, and summer fertilization. They can also be hand-pulled or mechanically removed.

Seeds of both plants can germinate from mid spring through summer when soil temperatures are greater than 55° to 60°F for 7 to 10 consecutive days and can continue germinating in soil temperatures to 95°F.