Weeds Identification Gallery

Crabgrasses

  • Digitaria spp.
  • Grass Family: Poaceae
Updated: 10/2025

Crabgrasses are summer annual grasses that generally grow in patches. They inhabit agricultural land and other disturbed sites. In California, large crabgrass, Digitaria sanguinalis, is more often found in gardens or landscape areas and smooth crabgrass, Digitaria ischaemum, is more often found in turf. They can provide good forage for livestock.

Habitat

Crop fields, orchards, vineyards, gardens, landscaped areas, turf, nurseries, pastures, roadsides, ditches, and other disturbed places.

A view of the stems and leaves of mature smooth crabgrass, Digitaria ischaemum. Credit: Clyde L. Elmore
Smooth crabgrass. Credit: Clyde L. Elmore

Mature Plant

Stems mostly branch at the base, are flattened in cross-section, and grow upright or prostrate. Leaves are flat, rolled in the bud and have a prominent midvein. Sheaths are open and flattened. Lower stems may root at stem joints (nodes) and the root system is fibrous.

Flowering stalk showing spikelets, 1/2X; . Credit: Jack Kelly Clark, UC IPM
Large crabgrass. Credit: Jack Kelly Clark, UC IPM

Collar Region

Ligules are membranous. There are no auricles.

Collar regions showing firm, membranous ligules and absence of auricles; . Credit: Jack Kelly Clark, UC IPM
Hairy crabgrass collar. Credit: Jack Kelly Clark, UC IPM

Flowers

Their flower heads have spikelike branches in one, or more often, two whorls at the stem tip. The spikelets that originate from the main stem are found at 1/8 to 1/4 of an inch (0.3–0.6 cm) intervals. The branches are 1/2 to 2-1/2 inches (1.3–6.4 cm) long.

Seedling showing tufts of hair at the margin of the collar, . Credit: Jack Kelly Clark, UC IPM
Smooth crabgrass seedling. Credit: Jack Kelly Clark, UC IPM

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