Lawn Guardian

How to Get Rid of Black Medic

Medicago lupulina

broadleaf weedUSDA zones 3–10Active: spring, summer

Low-growing annual legume often confused with clover. Produces small yellow flower clusters and distinctive black kidney-shaped seed pods.

How to identify it

Trifoliate leaves with tiny point at center leaflet tip; small bright yellow ball-shaped flower clusters; black coiled seed pods.

Treatment options

Cultural (prevention): Increase nitrogen

Black medic thrives in low-nitrogen soil. Proper fertilization favors turf over legumes.

When: Fertilize per soil test; emphasis on fall and spring

Cultural (prevention): Hand pulling

Shallow roots make pulling easy. Remove before seed pods turn black and drop.

When: Pull in late spring before seeds mature

Organic: Corn gluten meal

Spring pre-emergent reduces black medic germination.

When: Apply in early spring

Chemical: Triclopyr herbicide

More effective than 2,4-D for black medic and other legumes.

When: Apply when actively growing in spring or fall

Active ingredient: Triclopyr — e.g. Turflon Ester, T-Zone

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 black medic 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