Corn speedwell is a winter annual that germinates in mid-fall. Speedwells have a short taproot to fibrous root systems and branching upright stems. The lower leaves are near round with toothed margins. The upper leaves are more pointed. The plant is covered with fine hairs. Corn speedwell flowers are small and white to blue in color. The flowers are found in the leaf axis and the seed develops into a distinctive heart shape. Corn speedwell is distributed throughout the United States.
The competitiveness of corn speedwell can be reduced by maintaining a dense stand of turfgrass. Fertilize in the fall and maintain good disease and insect control programs.
Chemical control may be needed to eliminate invading corn speedwell, especially in turfgrass areas which are thin, or in newly seeded areas. Use a selective post-emergence herbicide taking care to follow spray intervals for newly seeded areas. For optimum control, make herbicide applications to actively growing speedwell in the four leaf to flower stage.