Large crabgrass

August 10, 2015

Digitaria sanguinalis (L.) Scop.

Life cycle

Prostrate to ascending summer annual.

Leaves

Both leaf surfaces and sheath are densely hairy. Leaves are rolled in the bud and more numerous at the base. Leaves are generally shorter, wider and more tapered than those of most other grasses.

large crabgrass seedling
Large crabgrass seedling.

Ligule

Jagged, membranous ligule.

Stems

Prostrate to ascending stems may reach 3 feet tall, capable of rooting at the nodes. Mature stems are often compressed in cross-section.

large crabgrass ligule
Large crabgrass collar region.

Flowers and fruit

The seedhead is a terminal panicle that consists of a few to several slender, fingerlike branches arranged in a whorl. Each plant is capable of producing thousands of yellowish brown, narrow oval to lance-shaped seeds.

large crabgrass seedhead
Large crabgrass seedhead.

Reproduction

Seeds.

Similar weeds

Smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] Differs by having a smaller stature, hairless to sparsely hairy leaves and sheath, a tuft of long hairs at the collar region and stems that do not root at the nodes.

smooth crabgrass ligule smooth crabgrass plant
Smooth crabgrass collar region (left). Smooth crabgrass plant (right).

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