Stephen Albert
Crabgrass is an annual summer weed. It infests lawns, vegetables gardens, ornamental gardens, orchards, and vineyards.
Description and Life Cycle:
- Plant 4/5 to 1⅓ inch tall.
- Stems (called culms) are erect and prostrate.
- Flat, pale green leaves, either smooth or covered with coarse hairs; membranous sheath on the inside of leaf blade.
- Leaves alternate on stem.
- Commonly forms a dense mat.
- Shallow rooted.
- Florets grow in terminal racemes on upright stems, often purple; blooms late summer.
- Reproduces by seed and by roots growing from swollen joints in the stems.
- Single plant can produce 8,000 seeds.
- Prefers dry and sandy soil.
Root System: Crabgrass has a shallow central root. Stems sprawl like a crab from the crown. The plant can set down new roots from swollen joints or nodes along the spreading stem.
Organic Control:
- Dig out crown of plant and remove the central root and all stems.
- Pull up plants before they set seed. Stopping seed production is the best control.
- Mulch with wood chips or landscape fabric to block sunlight and seed germination; spread a fine mulch 2 to 3 inches thick.
- Remove any plants that emerge from mulch before they spread new seed.
Range: Throughout the United States with exception of southern Florida and Southwest.
Botanical Name: Digitaria, various species
Four Quick Ways to Control Weeds:
- Weed early. Control weeds in the first month after they germinate.
- Weed often. Hand weed every two weeks through the season.
- Weed by hand when the soil is wet (best to get roots).
- Use a hoe if the soil is dry. Decapitate weeds before they flower and drop seed.
