A common weed in many lawns is ground ivy (Glechoma hederacea). Ground ivy is a low-growing, creeping, invasive perennial. It spreads by seed and the vining stems which root at their nodes. The leaves of ground ivy are round or kidney-shaped with scalloped margins. Stems are four-sided. Flowers are small, bluish-purple, and funnel-shaped. Ground ivy thrives in damp, shady areas, but also grows well in sunny locations. A member of the mint family, ground ivy produces a minty odor when cut or crushed. Ground ivy is also known as "creeping charlie."
Control of ground ivy in lawns is difficult. The key to control is the use of the proper broadleaf herbicide. The most effective broadleaf herbicide products are those that contain dicamba. Trimec and Ortho's Weed-B-Gon Weed Killer for Lawns are two widely sold products that contain dicamba. Fall (mid-September through early November) is generally the best time to control ground ivy. Two applications are usually necessary. The second application should be 14 days after the first. As always, when using pesticides, read and follow label directions carefully.
Ground ivy infested areas that contain very little grass should be completely destroyed and the turfgrass reestablished by seeding or sodding. The small amount of grass is simply not worth saving. Ground ivy infested areas can be destroyed by using the non-selective herbicide glyphosate (Roundup) or by tilling and removing the plant debris. When seeding shady areas, be sure to select seed mixes that contain shade-tolerant grass species.
Once the ground ivy has been effectively controlled and a healthy lawn reestablished, the home gardener needs to use good mowing, fertilization, watering, and cultivation practices to maintain a dense, healthy, competitive stand of turfgrass that should help discourage future invasions of this aggressive weed.
Borax and Ground Ivy
In the early 1990s, research at Iowa State University found that borax (sodium tetraborate) can be used to selectively control ground ivy in turfgrass. Borax contains the element boron. All plants require small amounts of boron for growth. However, boron becomes toxic when large quantities are present in the soil. Sensitivity to boron varies greatly between plant species. Borax can be used to control ground ivy in turfgrass because the ground ivy is more sensitive to boron than the cool-season turfgrasses.
To selectively control ground ivy in turfgrass, dissolve 10 ounces of borax in 2 to 3 gallons of water and apply the solution uniformly to 1,000 square feet. Selectivity is achieved by applying a specific amount of borax to a given area. Problems may occur if the borax solution is misapplied. For example, if the solution containing 10 ounces of borax is applied to only 250 square feet, both the ground ivy and the turfgrass may be destroyed. For small areas, dissolve 5 teaspoons of borax in 1 quart of water and apply the solution uniformly to 25 square feet.
This article originally appeared in the 10/10/2003 issue.