Spring Weed Control in "Dormant" Centipedegrass

Jeff Derr, Professor of Weed Science, Virginia Tech
 

The following was an inquiry from a Virginia Coopeative Extension Agent and was answered by Dr. Derr.

QUESTION (VCE Agent): "I have a homeowner that has a centipedegrass lawn and they are seeing some patchy cool-season grass weeds growing throughout the lawn. They mentioned that the centipedegrass is beginning to green up and break dormancy now, so I believe a dormant application of spot treatment with glyphosate may not be a good option now. Are you aware of any products that can be applied post-emergence to help with this now, or is hand removal the best option?"

ANSWER (Dr. Derr): They should not apply a glyphosate product.  Atrazine is an option and is available to homeowners.  In general we prefer to avoid herbicide applications during spring greenup, instead preferring to apply either dormant or after greenup.

FOLLOW-UP QUESTION (VCE Agent): "Are there specific products that you would recommend that contain atrazine formulations for homeowners, and at what rates would you recommend? And if post-greenup is the next available window, would you recommend to wait until early June or sometime in that window to apply?"

ANSWER (Dr. Derr): Hi-Yield Atrazine at 4 fl oz/gallon to treat 500 square feet.  If they can do so, have them spot spray the worst areas. I would not want those grassy weeds to get too big and that would be my concern for waiting until spring greening is complete.