Creeping Charlie (Glechoma hederacea) is an invasive perennial plant found in lawns. Once it emerges, creeping Charlie begins spreading, choking out the grass and replacing it with itself. Creeping Charlie often begins in shady, moist areas of the lawn, such as under trees, but it will spread throughout the entire lawn if given the opportunity.
Borax has been used as an effective treatment against creeping Charlie since 1920. The active ingredient in borax is boron, a micronutrient that helps plants transport sugars. When present in even small excess, it becomes toxic to creeping Charlie. To use borax as a creeping Charlie treatment, mix 10 oz. of borax with 2-1/2 gallons of warm water. This will treat 1,000 square feet of infested lawn. Apply the mixture with a sprayer, directly onto the creeping Charlie leaves, in the spring. If applied sparingly this treatment should not affect the surrounding lawn, but excessive or repeat applications may kill off grass.
Herbicides containing 2,4-D and MCPP, two chemicals often found in postemergence herbicides, are effective against creeping Charlie. Apply this herbicide in the fall, once outside temperatures have reached 70 F or lower, for the best results. Applications should be carried out when there is no chance of precipitation for the next 48 hours, as rainfall within this period will dilute the herbicide and render it ineffective. If the creeping Charlie in your lawn has spread and taken over significant portions of your lawn, an herbicide that also contains dicamba is another option. When applying a herbicide that contains dicamba only apply enough to wet the leaves of the creeping Charlie, as dicamba is absorbed through both the leaves and roots of plants and you run the risk of killing any portions of your lawn that absorb this chemical.
Removal of the creeping Charlie plant is possible manually if the plant has only just begun to invade your lawn. Creeping Charlie often appears first in shady sections of lawns. Pull the plants out by hand or with dethatching rake. The key to keeping creeping Charlie away once removed is to seed the area with shade-tolerant grass. By replacing sparse, shady areas with a blanket of lush, shade-loving grass it prevents creeping Charlie from taking hold. The best time to seed the area is in the late summer to early fall.