I receive several calls each year inquiring about the use of nonselective herbicides (those that kill all green vegetation) over dormant turfgrass to control winter annual weeds. While there are products on the market that are labeled for such application my advice is to carefully assess your particular situation and explore all alternative options as well. These products are generally very specific as to which turf species can be treated and severe injury may occur to species not labeled.
Even after the blast of cold weather we received back in early December, extreme care needs to be taken that the application is made to completely dormant turf. The recent warm temperatures may have created some new growth in many lawns.
You need to survey your lawn very carefully for any spots that may be protected from the cold and exposed to the warmth of the sun that would be injured from nonselective herbicides if applied to those areas. Identify the winter weeds present and see if there is other labeled herbicide choices for control without risk to the desired turf. Some of these winter annuals can be effectively managed simply by mowing.
Published January 3, 2005
Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. firstname.lastname@example.org