Black nightshade Solanum nigrum
IDENTIFICATION — This rambling, 1- to 2-ft.-tall annual weed blooms all summer with clusters of star-shaped white flowers with yellow centers. Large quantities of berries turn dull black when ripe and are toxic to humans and animals but are eaten by birds. Each berry contains up to 60 seeds.
FAVORITE CONDITIONS — Black nightshade grows in sun or shade almost anywhere but prefers rich, moist soil.
CONTROL — Before it sets seed, pull and remove all parts of the plant. Even small stem pieces dropped on the ground can root and regrow. A pre-emergent herbicide, such as Dacthal, can be applied in the spring to prevent seed from germinating.