For chemical control, use a pre-emergence herbicide containing isoxaben to prevent seedlings from becoming established in lawns and around ornamentals. For post-emergence control in lawns, use a product containing MCPA, MCPP, and dicamba. Back to top Crabgrass. This infamous summer annual thrives in hot, moist areas. It's a shallow-rooted weed that flourishes in underfed lawns, in poorly drained areas, and in lawns and flower beds that receive frequent surface watering.
Seeds germinate in early spring in southern climates, later in northern areas.
In flower beds, pull crabgrass before it sets seed. To thwart crabgrass in lawns, keep the turf well fertilized and vigorous, so it will provide tough competition for weeds. Solarization can control crabgrass if high temperatures are achieved. Back to top Dandelion. Familiar as a lawn weed everywhere in the United States, dandelion is particularly troublesome in cold-winter climates.