Creeping Charlie, or Glechoma hederacea, is a persistent, low-growing perennial weed that frequently invades lawns and gardens across North America. This aggressive plant, a member of the mint family, forms dense, undesirable mats that can quickly smother turfgrass. Its success is due to an efficient reproductive strategy and its ability to thrive in conditions where many turf varieties struggle. Effectively removing this weed and preventing its return requires a comprehensive approach that addresses both its biology and the environmental factors supporting its growth.
Understanding Creeping Charlie’s Growth Structure
The difficulty in controlling Creeping Charlie stems directly from its unique anatomy and reproductive method. The plant features characteristic square stems and spreads primarily through long, horizontal, above-ground runners known as stolons. These stolons can extend over seven feet in length and are the main driver of its quick, carpet-like spread across an area.
The stolons produce roots at nearly every node (where leaves join the stem), allowing the plant to establish new, independent individuals (ramets) as it creeps along the ground. Since the plant regenerates from tiny pieces of stem or root, simple manual pulling often breaks the stolons and inadvertently helps the weed propagate, making eradication challenging. Creeping Charlie prefers moist, shady conditions and poorly drained soils, giving it a competitive advantage where grass is weak.
Non-Chemical Control Methods
Manual removal can be effective for small infestations or near vegetable gardens where chemical use is a concern, but it requires diligence. The crucial step is ensuring the entire stolon system, including all rooted nodes, is removed from the soil. Working the soil when it is thoroughly moist, such as after a deep watering or heavy rain, makes it easier to extract the entire plant network without breaking off pieces. Any fragment left behind can re-root, restarting the infestation.
Cultural control methods can eliminate or weaken larger patches. Smothering the weed by covering the infested area with an opaque material, such as black plastic sheeting or thick layers of cardboard, deprives the plant of necessary sunlight. The material must remain in place for several weeks to ensure the plant dies completely before the area is reseeded. Improving soil conditions is another technique; since Creeping Charlie prefers soil with a pH between 5.5 and 7.5, applying lime to raise the soil pH slightly can make the environment less favorable, though this should be based on a soil test.
Targeted Chemical Eradication
For widespread or deeply established infestations, systemic broadleaf herbicides are the most effective method of control. Since Creeping Charlie has waxy leaves, traditional 2,4-D-only products are often ineffective. Successful chemical treatments contain a combination of active ingredients, such as 2,4-D, dicamba, and triclopyr. Triclopyr is particularly effective against this weed.
These products act as systemic weed killers, meaning the chemical is absorbed by the foliage and translocated throughout the entire plant, including the stolons and roots. This internal movement is essential for killing the entire perennial structure, making proper timing important. The optimal time for application is late fall (late September through November), after the first light frost but while the leaves are still green and active. During this period, the plant is naturally drawing nutrients down to its root system to prepare for winter, maximizing the translocation of the herbicide into the roots.
A secondary application in the spring, when the plant is actively growing and flowering, can address any surviving patches. Liquid formulations are generally more effective than granular products because they provide better coverage of the weed’s low-growing leaves, enhancing absorption. Spot treatments are recommended to minimize the impact on surrounding grass. Avoid spraying near the root zones of shallow-rooted trees and shrubs, as the chemical can cause damage.
Long-Term Lawn Health and Prevention
Once Creeping Charlie is eradicated, the focus must shift to modifying the environment to prevent its reestablishment. Since the weed thrives in moist, shady, and poorly drained areas, improving these conditions is the best long-term defense. Overseeding the lawn with competitive, dense turfgrass varieties is important to crowd out any potential new invaders.
Adjusting cultural practices can reduce the weed’s ability to compete. Raising the mowing height to between 2.5 and 3 inches encourages the grass blades to shade the soil surface, making it difficult for the low-growing weed to germinate and establish. Proper watering should be deep and infrequent to discourage the damp soil conditions that Creeping Charlie prefers. Addressing underlying soil issues such as compaction or poor drainage through aeration will promote stronger, healthier grass roots, creating a lawn environment that is inhospitable to this weed.