Common Name: crabgrass, smooth
Species: Digitaria ischaemum (Schreb.) Schreb. ex Muhl.
Bayer Code: DIGIS

Smooth crabgrass germinates from March through early May in North Carolina when soil temperatures reach 53 to 58°F at a 4-inch depth. Alternating dry and wet conditions at the soil surface in the spring encourage germination. Crabgrass germinates and grows best when adequate light and moisture are present. Stems have a prostrate growth habit and may root at the lower nodes. Smooth crabgrass is similar to large crabgrass, but the leaf blade of large crabgrass has more hairs, with short hairs on both surfaces, and scattered hairs on the edges.
smooth crabgrass in turf
[Click on image to view plant details]
smooth crabgrass rolled vernation
smooth crabgrass
smooth crabgrass ligule
smooth crabgrass
Seedhead / Flower raceme2 - 6 spikes at top of stems
Vernation Type rolledleaves rolled in the bud
Ligule Type membranous0.06 - 0.12 inches (1.5 - 3 mm) long, blunt to collar-like, slightly wavy
Growth Season / Life Cycle summer annual weed 
Auricle Type absent 
Leaf Blade Tip Shape sharp-pointedsmooth above, with mostly a few hairs near base, edges not hairy or sparse hairs along edge, dull green or tinged with purple
Leaf Blade Width broad, greater than 0.2 in0.2 - 0.4 inches (5 - 10 mm) wide
Stolon Presence present 
Rhizome Presence absent 
Collar Type  often divided, distinct, few hairs at the edge
Sheath Margin open 
Sheath Type flattenedsheath is not hairy, lower sheaths may be sparsely hairy