We received an email the other day asking about the best way to control Black Medic on a home lawn.
Black Medic (Medicago lupulina) is a difficult to control weed due to its small leaf size and the waxy cuticle on the leaf that reduces absorption of the weed management product.
It normally takes 2-3 applications to start reducing the prevalence of black medic.
In the meanwhile, the most important parts of weed management are fertilizing the lawn to crowd out weeds and thicken the lawn, proper deep watering (as weeds invade weak lawns), and mowing properly and often. (Mowing also helps thicken the lawn. Plus bagging clippings when the weeds are in flower helps as the flowers produce seeds creating new weeds to contend with.)