Every year one of the most popular questions we get as master gardeners is “how do I kill the creeping Charlie in my lawn?” I am often reminded of what Professor Leon Snyder used to say about ground ivy — “learn to love it.” Dr. Snyder was one of the originators of the University of Minnesota Landscape Arboretum in Chanhassen and a very knowledgeable gentleman.
Other information I have come across in recent days of cleaning out files is words of wisdom from Deborah Brown, another retired Extension Horticulturist from the University of Minnesota. When she was at the University, word was out about the efficacy of using Borax on creeping Charlie.
You might have heard of this solution. She said it works fairly well, but you can’t keep applying it year after year.
Two years is probably about all that’s safe, because boron collects in the soil and will kill the grass if there is too much. Then you’d have to scrape away and replace the top soil because the boron won’t break down and disappear.
Her other words of wisdom are if the creeping Charlie is growing in a shady place where it’s difficult to grow grass, she would think long and hard before killing it. She said unless you have a good plan for the area and know what will replace the creeping Charlie, you’re better off leaving it as is.
Once the creeping charlie is gone, you need to do all you can to encourage the remaining grass to grow as vigorously as possible, including regular mowing, fertilizing, watering when necessary, thatch control, etc. If you can’t create a thick, healthy stand of grass or other groundcover, it will just fill in with weeds again.
More recent recommendations from the University of Minnesota include the following if creeping Charlie is in your lawn:
Hand removal is effective for removing small patches but may need to be repeated. Remove all parts of the roots and shoots to prevent regrowth. A dense and healthy turf is the best defense against ground ivy encroachment. Ground ivy re-establishes quickly but can be controlled with postemergence herbicides containing triclopyr. 2,4-D is not very effective in control.Chemical control is most effective in the fall. If needed, spring application is also effective. In the fall, ground ivy sends herbicides to its roots along with nutrients.
A word of caution if creeping Charlie is in your garden: Broadleaf herbicides can be effective on large patches but can adversely affect desired garden plants.
Another caution: Always follow pesticide label directions attached to the container. Be sure that the area you wish to treat is listed on the label of the pesticide you intend to use. Remember, the label is the law.
Master Gardener Sue Morris has been writing a column since 1991 for Kandiyohi County newspapers. Morris has been certified through the University of Minnesota as a gardening and horticulture expert since 1983. She lives in Kandiyohi County.
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