Released March 21, 2008
MOUNTAIN HOME, Ark. -- Prevention is the best method of controlling weeds in a lawn, according to Mark Keaton, Baxter County extension agent with the University of Arkansas Division of Agriculture.
"The most effective way to control weeds in a lawn is a dense, vigorous turf," he said. "Any practice which helps produce thick turf discourages weeds. Chemical herbicides are available to supplement good management for controlling problem weeds."
If broadleaf weeds pop up and become a nuisance, use post-emergence products such as phenoxy herbicides, Keaton said.
Phenoxy herbicides include 2,4-D, dicamba, dichlorprop, mecoprop and various combinations of these. Since they’re for broadleaf weed control, they’ll have little effect on most grasses.
"However, don’t use phenoxy herbicides on a warm-season lawn during the spring green-up period, because injury to your lawn can occur," Keaton cautioned.
The various three-way combinations of phenoxy herbicides such as Trimec Classic, Trimec Southern and Weed-B-Gon are more expensive but will control a broader spectrum of broadleaf weeds than one herbicide alone.
"Use extreme caution to avoid spray drift when applying a phenoxy herbicide," Keaton warned. "Plants such as tomatoes, okra, roses and many shrubs can be injured or killed by herbicide drift."
For the most effective weed control, phenoxy herbicides should be applied when weeds are small (two- to four-leaf stage), there is good soil moisture and the temperature is between 60 to 90 degrees Fahrenheit for eight to 10 hours for all phenoxy herbicide applications. Apply the herbicide when there is no rain in the forecast for the next 24 hours.
Use 2,4-D products for control of wild garlic, dandelion, henbit, chickweed, plaintain, dock species and other broadleaf weeds. Use a higher rate on wild garlic than on other broadleaf weeds. Using 2,4-D in combination with dichlorprop or mecoprop and dicamba on most annual and perennial broadleaf weeds does a better job than 2,4-D alone.
"With all herbicides, read and follow the label directions and precautions," Keaton advised.
Always wash sprayers with soap and water after using a phenoxy herbicide. Then, put three tablespoons of ammonia cleaner per gallon of water in sprayers and let the solutions sit for 24 hours. Rinse sprayers again before using.
Use different sprayers to apply lawn herbicides or to spray an insecticide or fungicide on vegetables, trees, shrubs or flowers. Residual herbicide left in the sprayer can injure or kill the plants, even if the sprayer was cleaned.
For more information on lawns, contact your county extension agent or visit http://www.uaex.edu and select Home and Garden. For contact information for your agent, go to http://www.uaex.edu and select Personnel Directory, then Cooperative Extension Service.
For help identifying weeds by name, use the Search link at the top of the Web page.
The Cooperative Extension Service is part of the U of A Division of Agriculture.
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http://www.uaex.edu/news/march2008/0321lawns.htm
Contact: Lamar James, (501) 671-2187 or (501) 753-0207, ljames@uaex.edu
