- Written by Robbi Hoy
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Yikes! So many times I get calls about that little invader, Creeping Charlie (Glechoma hederacea). It is despised by almost everyone so the calls about how to get rid of it, are frequent. This little weed can be very difficult to get rid of, especially in areas that get regular moisture and are in partial shade due to trees, shrubs or in the shadows of our homes. When I am asked about Creeping Charlie, I always share the information that the University of Minnesota Extension office has published. Here is what they say about getting rid of our not so friendly Charlie.
"Stems grow primarily on top of the soil and will root at nodes (where leaves come in contact with stems). Well-anchored stems hugging the soil avoid damage from lawn mowers and can be challenging to pull out. Fortunately, the unique growth habit of this weed provides us with a window of opportunity in spring where it is easier to remove. Our long, cold winters weaken roots of creeping charlie. Before plants recover by generating new roots from stem tissue laying on top of the ground and repairing some of the old roots, there is a time that the stems are poorly anchored to the ground. This is typically in March/April after the ground thaws and the soil is moist, but before temperatures have risen enough to encourage active growth. At this time one can readily lift stems with a pitch fork, a rake, or even by hand and discard them."
"Manually pulling creeping charlie early in the season when it is more amenable to removal is a very useful method to get it out from between established herbaceous perennials and shrubs. Within established herbaceous perennial and shrub plantings, often physical removal is the only realistic and safe option. Creeping charlie is relatively herbicide resistant and may require repeated applications, an added challenge to removal and one that can put adjacent, herbicide-sensitive landscape plants at risk."
"Removing creeping charlie manually from lawns can be especially daunting due to intermingled grass and creeping charlie stems and roots. Combinations of herbicides including 2, 4-D, MCPP, and/or triclopyr can kill creeping charlie, however, repeated applications are often necessary and applications in the early fall or in spring when the plant is flowering are often more effective than other times during the growing season."
"If a standard herbicide labeled for creeping charlie or manual removal of creeping charlie are not acceptable options for eradication in lawns, a very careful application of borax (sodium tetraborate) may work. Boron is essential for plant growth, but in excess can easily kill plants. Creeping charlie has a lower boron toxicity threshold than grasses and by carefully controlling the application rate one can kill creeping charlie, but keep turf alive. The pH of the soil, soil type, and weather all influence the effectiveness of borax on killing creeping charlie. Although it can be effective, the use of borax for creeping Charlie control in turf is generally not recommended due to variable results and the risk of toxic levels of boron which will be difficult to leach from the soil. Since most broadleaf plants are relatively sensitive to boron toxicity and little is known about the boron tolerance of most broadleaf woody and herbaceous plant materials, borax should definitely not be used on non-turf areas."
"Be aware of what is sold as variegated glechoma in the garden centers (variegated creeping charlie). It is often sold in spring in small pots for use as a foliage accent in hanging baskets or window boxes or for use as a colorful groundcover. It does overwinter in Minnesota and frequently more aggressive solid green sections sport from variegated plants. Timely removal of green sections or seedlings and generally keeping variegated creeping charlie in bounds will help prevent it from becoming a weed problem."
"Consider saying goodbye to creeping charlie from ornamental landscape plantings by manual removal during the upcoming window of opportunity. Allowing this unwelcome guest to get a foothold early in the season will only make it more difficult to remove later. As the season progresses creeping charlie stems only become more strongly rooted and actively growing landscape plants become more difficult to navigate between."Source: University of Minnesota ExtensionImages: Creeping Charlie by Creeping Charlie by by The NYSIPM; Variegated Creeping Charlie by Patrick Standish