University of Illinois Extension

 


Bruce Spangenberg
Extension Educator, Horticulture
Rockford Extension Center

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Control Perennial Grassy Weeds

Perennial grasses such as creeping bentgrass, nimblewill, zoysiagrass, tall fescue, and quackgrass can become weed problems in Kentucky bluegrass lawns. August is a good time to control these weed problems. Removing these weed patches by hand is one control option. It's important to get all of the plant, as many have underground or above ground stems (rhizomes or stolons) that allow these species to spread quite readily, so if broken or cut, they regrow.

Nonselective herbicides such as glyphosate (Roundup, Kleeraway) can be used to control perennial weed grasses, but remember desirable lawn species will also be damaged. For this reason, spraying over the lawn is not suggested unless the problem is severe enough that all grasses need to be killed and the lawn reestablished. Patches of the undesirable species can be spot treated. After weeds and portions of lawn hit with spray die, reseed with lawn grass species.

Treating in mid-August is generally thought of as the best timing (late July to early August to control nimblewill and zoysiagrass), as late August into early September is the most favorable time for reseeding. If resodding the area afterwards, there is a longer period of time to treat the weeds. Remember weeds need to be actively growing to be controlled by glyphosate, however. Allow 10 to 14 days to determine if weeds have been completely controlled.

 

August - September 2001: Watering Correctly Saves Time, Money, and Plants | Gourd Success Includes Proper Harvest & Handling | Harvesting & Handling Sunflowers | Early Fall Key Time for Lawn Fertilization | Control Perennial Grassy Weeds

 

Past Issues

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