Controlling weeds in turfgrass

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Besides dandelion that is flowering everywhere in turf right now, there are numerous other weeds that are displaying their best spring colors. For some of these weeds the flowering period in the spring is the second best time to apply a herbicide for control, fall is the best, but for other weeds this spring flowering is a sign that their life is about over. Proper identification of what weed you are dealing with can save you time and money. Currently common chickweed, henbit, shepherd's purse, yellow rocket, and corn speedwell are all flowering. Without understanding their life cycle, some might think this is a great time to control these weeds. However, these weeds are all winter annuals which mean they germinate in the fall, overwinter, and then flower and produce seed in the spring. If you apply an herbicide now, they will be dead and gone in two to three weeks. However, if you do nothing it could take as long as 14 to 21 days before they’re gone. Let that sink in for a moment before you plan your weekend.

Perennial weeds that are flowering throughout many areas of Michigan include creeping speedwell, germander speedwell, ground ivy, and wild violet. Unlike the winter annuals, treating these perennial weeds with a broadleaf herbicide during the spring flowering period will be effective and will not be a waste of your time as these weeds will be sticking around all year. The best web resource for helping you identify weeds and understanding their life cycle is

Wild violet
Wild violet.  

Dr. Frank's work is funded in part by MSU's AgBioResearch.

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