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Plan Winter Weed Control Now

It still feels like summer, but it is already time to start thinking about winter weed control. Annual winter weeds germinate late summer through fall and slowly grow during the winter months. They flower and produce seeds in late winter and early spring. Luckily, there are a few practices that can limit winter weeds.

Preemergent herbicides can be used to limit annual weeds in the landscape. It is important to note that preemergent herbicides need to be applied before the seeds begin to germinate. Preemergent herbicides will not control perennial weeds or actively growing weeds.

Annual bluegrass a very common winter annual weed. Jackie Jordan, ©2021, Clemson Extension

Annual bluegrass a very common winter annual weed.
Jackie Jordan, ©2021, Clemson Extension

A common winter weed is annual bluegrass. Seeds germinate in autumn when soil temperatures drop below 70 °F. Preemergent herbicides should be applied when we receive four consecutive days with daytime highs at or below 75 °F. Preemergent herbicides need to be watered in with one-half inch of water within seven days of application. To learn how to calibrate your sprinkler system, watch the video How to Set and Calibrate Your Irrigation System. Preemergent herbicides can control many different weeds. For more information on Annual Bluegrass and preemergent herbicide recommendations, please see HGIC 2325, Annual Bluegrass Control and HGIC 2300, Grassy Weeds.

Seeds need consistent moisture during the germination process. Deep and infrequent irrigation can help to reduce weeds. Turfgrasses are pretty drought tolerant and only need irrigation once they begin to develop a slight blue-grey cast. For more tips on managing lawn irrigation, see HGIC 1207, Watering Lawns.

A majority of seeds need sunlight to germinate. Raising the mowing height of your lawn and keeping a three-inch-thick layer of mulch in landscape beds will significantly reduce annual winter weeds in your landscape. For recommended mowing heights, please see HGIC 1205, Mowing Lawns.

Common chickweed is an annual winter weed that needs light to germinate. Jackie Jordan, ©2021, Clemson Extension

Common chickweed is an annual winter weed that needs light to germinate.
Jackie Jordan, ©2021, Clemson Extension

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

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