Clover (Trifolium) is an annual flowering plant in the pea family. Because it readily reseeds, it can multiply rapidly and is considered a nuisance in residential lawns. If allowed to proliferate, clover will take over a lawn and shade the desired grass, killing it. Clover is a challenge to eradicate but a combination of proper cultural practices and selective herbicide will go a long way in ridding the lawn of the pest. Choose an herbicide that is labeled specifically to kill clover and that is safe to use on your type of grass.
Mow the lawn regularly and to the proper height for the type of grass being grown and fertilize it consistently. This will encourage the grass to grow stronger and thicker and it will choke out the clover.
Cut back on watering during rainy periods. Clover becomes more aggressive in wet soils.
Test the soil prior to using potassium fertilizer as potassium encourages clover growth.
Kill existing clover by spraying it with an herbicide. Pour the herbicide into the tank sprayer at the rate suggested on the label.
Walk across the lawn backwards, spraying in front of you in a broad, even, side-to-side fashion. Do not water the lawn until the following day and keep people and pets off the lawn until the product has dried.