July 16, 2015
There are two weeds that occur in turf that almost everyone can identify: dandelion and white clover. In the last several weeks, it’d be hard not to notice the amount of white clover that is invading turf everywhere.
White clover is commonly found growing in low fertility, low maintenance sites, such as roadsides, home lawns and golf course rough. White clover is very competitive in low fertility sites because it, like other legumes, hosts rhizobacteria that fix atmospheric nitrogen into plant available nitrogen. To this point in the year, we have had more than abundant rainfall and relatively cool temperatures resulting in vigorous turfgrass growth. The growing conditions are likely resulting in fertilizer applications not lasting as long as usual and creating a perfect opportunity for white clover to invade.
In addition to the lack of fertility, it is difficult to keep up on mowing when the turf is growing this fast. Some homeowners may lower the mowing height to try and delay how soon they have to mow again. This results in removing more turf leaf tissue and encouraging white clover as white clover has a prostrate growth habit that often isn’t really touched by mowing.
A long-term strategy Michigan State University Extension recommends to reduce white clover competitiveness in turf is to ensure adequate fertility levels. For cool-season lawn height turf in Michigan, at a minimum I would suggest 2 pounds nitrogen (N) per 1,000 square feet per year split over two applications to ensure the turf is dense and competitive. Depending on the turf use and inherent soil fertility, more than 2 pounds N per 1,000 square feet may be necessary on many sites to produce a turf that is competitive with weeds.
Although fall broadleaf herbicide applications are very effective for controlling white clover, many homeowners and turf managers can’t wait until fall to begin controlling weeds. Herbicides that have excellent activity for controlling white clover in home lawns include those that contain the active ingredients fluroxypyr, triclopyr or quinclorac. For more information on white clover and other pesky turfgrass weeds, please visit MSU Turf Weeds.
Always read, understand and follow the label directions. Mention or exclusion of specific products does not represent an endorsement or condemnation of any product by Michigan State University.
Dr. Frank’s work is funded in part by MSU’s AgBioResearch.
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