Digitaria sanguinalis
grassy weedUSDA zones 3–10Active: summerAnnual summer grass that thrives in thin, stressed turf. Spreads aggressively from a central point forming star-shaped patches. Dies with first frost, leaving bare spots.
Wide, coarse blades growing in a star pattern from central crown; lighter green than surrounding turf; finger-like seed heads.
Mow at 3.5-4 inches to shade soil and prevent crabgrass germination. Crabgrass needs light to germinate.
When: Throughout growing season, especially spring
Fill bare spots with desirable grass seed to prevent crabgrass from establishing.
When: Fall overseeding for cool-season lawns
Natural pre-emergent that inhibits root development. Apply at 20 lbs per 1,000 sq ft.
When: Apply in early spring when forsythia blooms, before soil reaches 55F (soil ≥ 55°F)
Apply before crabgrass germinates. Creates a barrier in soil that prevents seedling emergence.
When: Apply when soil temperature reaches 55F at 4-inch depth for 3 consecutive days (soil ≥ 55°F)
Active ingredient: Prodiamine — e.g. Barricade, Quali-Pro Prodiamine
Kills actively growing crabgrass. Most effective on young plants (1-3 tillers).
When: Apply when crabgrass is young and actively growing, before it tillers heavily
Active ingredient: Quinclorac — e.g. Drive XLR8, Quinclorac 75 DF
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.
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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