Alehoof (Glechoma hederacea), also known as Ground Ivy or Creeping Charlie, is a widespread perennial plant in the mint family (Lamiaceae). Characterized by its creeping growth habit, it frequently appears in gardens, lawns, and natural areas. Its ability to spread quickly contributes to its common presence.
Identifying Alehoof
Alehoof is identified by its distinct physical characteristics. Its leaves are typically round to kidney-shaped with scalloped edges, and measure about 1/2 to 1 1/2 inches in diameter. These leaves are arranged oppositely on square-shaped stems, which may show a purplish or reddish tint in full sun. When crushed, the leaves and stems emit a mint-like or musky aroma. Small, funnel-shaped, blue, bluish-violet, or lavender flowers emerge in clusters from leaf axils, typically blooming in spring.
Understanding Alehoof’s Growth and Spread
Alehoof is an aggressive plant that spreads primarily through its creeping stems, known as stolons, which grow along the ground and root at each leaf node. This rooting ability allows the plant to form dense, mat-like patches, making it difficult to control. While it also produces seeds, vegetative reproduction through these rooting stems is its main method of expansion. The plant thrives particularly well in damp, shady conditions and rich, fertile soils, but it can also tolerate sunny locations. Its ability to outcompete other plants, including turfgrass, is attributed to its dense growth and allelopathic effects, where it produces biochemicals that inhibit the growth of surrounding vegetation. Even small fragments of stems or roots can regrow, contributing to its persistence and rapid colonization of disturbed areas.
Effective Control Methods for Alehoof
Controlling Alehoof requires a combination of approaches. For small infestations, manual removal is effective, especially when soil is moist. Remove all plant fragments, as even small pieces can re-root; therefore, removed material should be disposed of properly, not composted.
Cultural Practices
Cultural practices manage Alehoof by making the environment less favorable for its growth. Improving soil drainage, reducing excessive moisture, and increasing light penetration by pruning overgrown trees or shrubs can discourage its spread. Maintaining a healthy, dense lawn through appropriate fertilization, proper mowing heights (2.5 to 3.5 inches), and regular overseeding helps turfgrass outcompete Alehoof. Selecting shade-tolerant grass species for shaded areas also creates a more competitive environment.
Chemical Control
Herbicides with active ingredients like triclopyr, dicamba, or 2,4-D are recommended for broadleaf weed control. Triclopyr, alone or combined with 2,4-D, shows good results. The most effective time for application is typically fall (late September through early November) when the plant actively transports nutrients to its roots, allowing better herbicide absorption.
Multiple applications may be necessary. Follow label directions, avoid spraying on windy days to prevent drift, and protect desirable plants.
Traditional Uses and Important Considerations
Historically, Alehoof has been valued for various uses. One notable traditional use was in brewing, where it served as a flavoring, clarifying, and preservative agent for ale before hops became widely adopted in the 15th to 16th centuries. This historical use is reflected in its common names like “gill-over-the-ground.”
The plant has also been used in traditional medicine for centuries. European herbalists used it for various ailments, including respiratory conditions like coughs and bronchitis, digestive issues, kidney and bladder problems, and even for treating eye inflammation. It was also believed to have diuretic, astringent, and anti-inflammatory properties. Young leaves have been used raw in salads or cooked as a leafy green, and a tea can be made from the fresh or dried leaves.
Toxicity Considerations
Despite its historical uses, Alehoof has toxicity concerns. The plant is toxic to certain livestock, especially horses, if ingested in large quantities, whether fresh or in hay. Symptoms of poisoning in horses can include excessive salivation, sweating, and difficulty breathing.
While humans have consumed it, it may be slightly toxic to humans due to compounds like glechomin, potentially causing nausea if consumed in excess. Pregnant women and individuals with kidney disease or epilepsy are generally advised to avoid consumption. Cats and dogs may also experience mild toxicity if they ingest significant amounts, with symptoms such as gastrointestinal upset.