Creeping Charlie, officially known as Glechoma hederacea, is an invasive perennial weed that presents a formidable challenge to a manicured lawn. This species, also commonly called ground ivy, is a vigorous mat-former that aggressively crowds out turfgrass and other plants. Successfully managing this nuisance requires understanding its unique biology and employing a targeted strategy of cultural, physical, and chemical controls.
Understanding Creeping Charlie’s Aggressive Growth
The difficulty in managing Creeping Charlie stems directly from its specialized biological features and growth habit. As a member of the mint family, the plant possesses distinctive square stems and kidney-shaped leaves with scalloped edges. When crushed, the leaves release a strong, mint-like aroma that aids in identification.
The plant’s primary method of spread involves above-ground runners, called stolons, that creep along the soil surface. These stolons root aggressively at every node they encounter, enabling the plant to establish new colonies rapidly. This low-growing, dense mat of vegetation resists regular lawn mowing, allowing it to flourish beneath the cut height of turfgrass.
Creeping Charlie also possesses a significant competitive advantage over most common turf species due to its environmental tolerance. It thrives particularly well in shady and moist areas, conditions where lawn grasses struggle to grow dense and healthy. By colonizing these weakened areas first, it quickly monopolizes the resources, making it a persistent competitor.
Non-Chemical Strategies for Suppression
Modifying the lawn environment is the most effective long-term method to discourage the establishment and spread of ground ivy without herbicides. Since the plant favors damp, shaded conditions, improving drainage in low-lying spots can immediately reduce its competitive edge. Pruning lower tree limbs or thinning shrubbery to increase sunlight penetration will also make the area less hospitable to the weed.
Adjusting cultural practices to favor the turfgrass is another effective preventative measure. Raising the mowing height to between two and three and a half inches encourages the grass blades to grow taller and cast more shade on the ground ivy beneath. This increased competition for light helps to weaken the weed and prevents its runners from easily accessing the light they need to establish new roots.
For small, contained patches, physical removal is an option, though it is labor-intensive. Hand-pulling is challenging because every piece of stolon or root fragment left in the soil can re-root and generate a new plant. It is important to remove the entire root system and dispose of the pulled material properly to prevent fragments from establishing elsewhere.
Smothering or solarization can be used for larger, heavily infested areas where the grass has already been lost. Covering the area with thick black plastic or cardboard for several weeks blocks all sunlight, effectively killing the plant material beneath. Once the Creeping Charlie has died, the remaining material must be raked away before overseeding the area with turfgrass appropriate for the existing light conditions.
A common home remedy involves treating the weed with a solution of borax (sodium tetraborate), but this practice is not generally recommended by horticulture experts. Borax contains boron, a micronutrient that becomes toxic to plants in elevated amounts, and Creeping Charlie is especially sensitive to it. The margin between the dose needed to kill the weed and the dose that permanently sterilizes the soil is extremely narrow. Applying too much boron can accumulate in the soil, creating “toxic hot spots” where no plants, including lawn grass, can grow for years.
Effective Chemical Treatments and Timing
When non-chemical methods prove insufficient for large or persistent infestations, professional-grade broadleaf herbicides offer the most reliable control. Creeping Charlie is notoriously resistant to many common weed killers, particularly those containing only 2,4-D. Effective control requires herbicides that contain active ingredients such as triclopyr or dicamba, often formulated together in “three-way” broadleaf weed control products.
Timing the application of these systemic herbicides is crucial for maximum efficacy. The most optimal period is in the fall, typically from mid-September through early November, just before the first hard frost. During this time, the perennial weed actively moves sugars down to its root system for winter storage.
Applying the herbicide in the fall allows the chemical to be effectively translocated along with the sugars, delivering the active ingredient deep into the root structure. A secondary application can be made in the late spring when the plant is flowering, but the autumn treatment yields the most significant results. Because the weed is resilient, multiple applications over several seasons are often necessary to achieve complete eradication.
Herbicides should be applied as a spot treatment directly onto the leaves to ensure thorough coverage. Following all label instructions is necessary, including wearing personal protective equipment and avoiding application when rain is expected. To prevent damage to the lawn, avoid mowing for a few days before and after application to maximize the plant’s surface area for absorption.