What is the best way to get rid of creeping Charlie in my yard? It has taken over an entire area of my side yard and is creeping into the front yard. I have treated it repeatedly with weed killer, but it keeps coming back. — James, Racine.
Creeping Charlie, also known as ground ivy, was imported into this country as a ground cover. It does that job very well. Creeping Charlie greens up early in spring, retains dark green scalloped leaves well into the fall, and has very attractive lavender flowers in May. The plant creates a dense mat of foliage and forms the “perfect” ground cover. Some people learn to love it, but unfortunately, it most often chooses to make its home in the middle of a lawn where it is not welcome.
People have tried many home remedies to get rid of it. Borax does not work, and is not recommended (can cause long lasting boron toxicity). Salt is a terrible idea for weed control because it ruins the soil for plant growth. Vinegar may burn the leaves, but will not kill the roots. Pulling creeping Charlie can be a lifelong activity if the area is seriously infested.
If you choose to use chemicals to control the spread of creeping Charlie, select the correct product, follow the label to the letter, and apply it at the correct time for maximum effectiveness.
There are many broadleaf weed killer products available to use in the lawn. They typically contain one or more of these chemicals, 2,4-D, dicamba, MCPP (or mecoprop), triclopyr and/or carfentrazone. New research recently published from Purdue University indicates that products containing 2,4-D alone can take care of killing this broadleaf weed when applied in fall after frost, and using the single chemical worked better than the combination products. Mowing before or after the application had no effect on weed control with any of the products tested, so the main factor with control was the use of a single chemical at the end of October. The second time of year when plants are sensitive to chemical control is in May when they are flowering, but fall is by far the best time.
It is always a good idea to be cautious with any chemical application and to follow label directions, but many of the broadleaf weed control products sold for homeowner use on lawns contain the chemical “dicamba” which remains in the soil for a long time and can harm trees and shrubs. Dicamba is taken up by plant roots, in contrast with most broadleaf weed killers taken up by leaves. Products containing dicamba clearly state on their label “Do not apply more than twice a year.”
If creeping Charlie has taken over an area completely to the point that grass is not surviving, you might consider using a total vegetation killer that contains glyphosate. Some total vegetation killers may also contain other chemicals that will cause lasting effects on plants and inhibit seed germination. If you are planning on growing grass (or any other plant) in that area, read the label carefully before buying, and again before applying any product.
Or you could take an organic, smothering approach and cover the area with 10 to 15 layers of newspaper topped with either compost or mulch. If the area is shady and grass is not going to grow successfully there, mulch is a beautiful and healthy option for trees. If you are planning on replanting, with grass, ornamental shrubs, herbaceous perennial, or perhaps with herbs or vegetables, the compost covering is the way to go. After a few months you will be able to plant right through the compost. Keep your lawn healthy with proper fertilization, mowing and watering, and grass will out compete the weeds.
To learn more about maintaining a healthy lawn, visit our UW-Extension Horticulture website at http://hort.uwex.edu.
Master gardener volunteers serving as plant health advisers are able to answer your questions at email@example.com or by calling the Horticulture Helpline at 262-886-8451 (Ives Grove) or 262-767-2919 (Burlington).
Dr. Patti Nagai is the horticulture educator for Racine County UW-Extension. Submit your questions for the Journal Times Q&A column to Dr. Nagai at Patti.Nagai@goracine.org and put “Question for RJT” in the subject line.