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Weed Identification

hairy crabgrass



Scientific Name

Digitaria sanguinalis

Other Common Names:

purple crabgrass
large crabgrass

Synonyms (former Scientific Names):

Syntherisma sanguinalis
Panicum sanguinale


Large crabgrass germinates in the spring and competes with turf during the summer months. Crabgrass begins germinating when sustained soil temperatures are 55 degrees F and moisture is available. In Virginia (USA) plants usually begin germinating mid April to early May in the mountains, late March to late April in the piedmont, and early March to mid April on the coastal plain. Plants compete with turfgrass during the summer, set seed in the fall, and die with first frost.


Large crabgrass leaves are densely hairy on both surfaces. Hairs are long but stiff and erect. The collar area and stems are hairy and the ligule is a large membrane. Stems tend to trail along the ground and root at nodes.

Identifying Characteristics

Fat cotyledon (seed leaf), hairy on all leaves and stems, large membraneous ligule and three to five-branched seedhead on slender stalk.

Flower Seed Head

Seedheads are borne on slender stalks and consists of three to five spikelets in an open arrangement.

Seed Fruit

Seeds are flat and narrow; about 1.5 mm wide and 5 mm long.

Where Found

Large crabgrass is widely distributed and one of the most economically important weeds of turfgrass. Plants can be found in the lawn, under close cut such as a putting green, and in tilled areas such as a home garden.

Leaf Hair on Upper Surface

hairs from base to tip

Leaf Arrangement

rolled in bud

Mature Leaf Width

less than 5 mm
6 to 15 mm


flat or oval


multiple spikes

Root Structure


Life Cycle

summer annual


not present



Ligule Length

less than 1 mm
1-2 mm
2-3 mm

Plant Type