Common Lawn Weeds (Garden Weeds Series)

by Carol Sitarski

Master gardener volunteer Allegany County

Have you notice how many plants live in your lawn? A variety of beautiful species make your landscape beautiful, with colors and textures for you to enjoy. But did you know that some unwanted weeds may also be present? Some of them look like some of our favorite cover crops. Here some of the common weeds that can be present in your lawn:

Black medic is a spreading summer annual weed with clover-like leaves and small globe shaped yellow flowers (image A). It grows only in compacted soil, and only from seeds; each plant can have more than 6,000 seeds. The best control is to aerate the soil as this will alleviate the soil compaction or hand pulling before plant goes to seed. Hand pulling is easier after rain when soil is still damp. There are chemical products available but because of environment protection they are not recommended. A pre-emergent product can be used in Spring to prevent seeds from sprouting. Always reseed the area heavily after removal to prevent future spread. If you use chemical products always read the labels and make sure to wear the right personal protective equipment.

Ground ivy also called “Creeping Charlie” is a creeping perennial with tubular lavender flowers and scalloped leaves (image B). It prefers moist shaded areas but can grow in other places as well. Since it is in the mint family it will root along stems, and occasionally by seed. For areas in the shade try to increase sunlight through pruning. Hand pulling is effective, however, try to locate the root at the end of what can be long stems otherwise more can regrow. Chemical control is not recommended due to environmental concerns and since the ivy may be entwined with your grass or flowers they will also be affected.

Corn speedwell is a prostrate creeping annual that spreads by seed. (Image C). It has small, rounded leaves, light blue flowers with five petals, white center, and heart shaped seed pods. It favors low fertility soils, so maintain good turf quality by proper addition of nitrogen fertilizer, lawn mowing and proper turf seed to create a dense lawn for prevention of seed germination. You can also control by hand pulling after a rain to make it easier for pulling out roots. This is a winter annual weed that germinates in the fall or winter and grows during any warm weather, which may occur in the winter, but otherwise remains dormant during the winter. They resume growth, produce seed in the spring, and die as temperatures increase in late spring and early summer. Therefore, removing in Spring through pulling is the best way to prevent seed formation.

References:

Cornell CALS. Turfgrass and landscape weed ID. [online article] link: http://turfweeds.cals.cornell.edu/plants, https://extension.umd.edu/resource/weed-identification-photos-marylahttps://garden.org/learn/library/weeds/nd

University of Maryland Extension. Corn speedwell. [online article] link: https://extension.umd.edu/resource/corn-speedwell

Last updated December 20, 2023