A common weed in many lawns and gardens 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. (Two other compounds commonly used in broadleaf herbicides are 2,4-D, and MCPP. Neither material effectively controls ground ivy.) Trimec and Weed-B-Gon Lawn Weed Killer 2 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 10 to 14 days after the first. As always, when using pesticides, read and follow label directions carefully.
Once the ground ivy has been effectively controlled and an 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 which should help discourage future invasions of this aggressive weed.
Research at Iowa State University has found that borax (sodium tetraborate) will 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. If properly applied, borax can be used to control ground ivy in turfgrass because the ground ivy is more sensitive to boron than the cool- season turfgrasses.
A widely sold borax product is Twenty Mule Team Borax. Five teaspoons of borax dissolved in 1 quart of water and then applied uniformly to 25 square feet will destroy the ground ivy while causing minimal damage to the turfgrass. However, problems may occur if the borax solution is misapplied. For example, if the 1 quart mixture is applied to only 10 square feet, that would be too strong and may result in the death of both the ground ivy and the turfgrass. To treat large areas, dissolve 10 ounces of borax in 2 to 3 gallons of water and apply the solution uniformly to 1,000 square feet.
Borax should not be applied to flower and vegetable gardens. The boron may damage or destroy many of the flowers and vegetables. The best way to control ground ivy in garden areas is by hand pulling and hoeing. The key to effective control of ground ivy in gardens is persistence. Repeatedly pull and hoe the ground ivy (remove the plant debris to prevent it from rooting) until it has been eliminated. Once destroyed, maintain clean, weed-free borders around flower and vegetable gardens to prevent the ground ivy from "creeping" back in from adjacent areas.
This article originally appeared in the May 15, 1998 issue, pp. 57-58.