Found throughout the US, Black medic is a summer annual or perennial broad leaf weed depending on where you live. Often mistaken for Wood sorrel, its yellow flowers look very different than Wood sorrel’s blooms. Black medic produces small, bright yellow flowers that eventually form a tightly coiled black seed pod – hence the name. This legume prefers dry, sunny areas and can be found in lawns, fields and along roadsides. It spreads by seed and proper mowing, irrigation and fertilization can help manage it. Control is easier before flowering and seed set. Hand pulling will work for individual larger plants and is best done when the soil is moist, so the whole plant and tap root can be removed. Postemergence herbicides can be used if management and hand pulling does not elicit control.

https://assessment.ifas.ufl.edu/assessments/medicago-lupulina/

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