Lawn Guardian

How to Get Rid of Barnyardgrass

Echinochloa crus-galli

grassy weedUSDA zones 3–10Active: summer

Coarse summer annual that grows vigorously in moist, fertile areas. Can grow 3-4 feet tall and produces large, purplish seed heads.

How to identify it

No ligule (key identifier); wide, coarse blades; purplish-red seed heads; grows in clumps; often in moist low spots.

Treatment options

Cultural (prevention): Maintain thick turf

Barnyardgrass invades thin, moist areas. Improve drainage and turf density.

When: Overseed thin areas; improve drainage

Organic: Hand pulling

Pull young plants including roots before seed heads form.

When: Pull in early summer

Chemical: Pre-emergent (prodiamine)

Spring pre-emergent prevents barnyardgrass germination.

When: Apply when soil temperature reaches 55F (soil ≥ 55°F)

Active ingredient: Prodiamine — e.g. Barricade

Chemical: Post-emergent (quinclorac)

Controls young barnyardgrass plants.

When: Apply to young plants before tillering

Active ingredient: Quinclorac — e.g. Drive XLR8

Grass safety: always match herbicides to your grass species — products safe on Kentucky bluegrass can kill St. Augustine or centipede. Lawn Guardian checks this automatically against your lawn profile.

Stop barnyardgrass at the right moment, automatically

Lawn Guardian turns this guidance into a schedule timed to your USDA zone and this week's actual weather — and adapts every time you log what you've done.

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Related weeds

Sources: Purdue University Turfgrass Science: Use Growing Degree Days to Better Time Your Applications · University of Missouri Extension: Cool-Season Grasses: Lawn Maintenance Calendar · University of Minnesota Extension: Pre-emergent Herbicides for Crabgrass Control in Lawns