Richard Evans, Contributor.
Summer brings a lot of different things, both good and bad. You have vacations, swimming, picnics, heat and…weeds! In my yard, I usually just let the weeds grow and mow them with the grass. However, I know that isn’t how everyone thinks.
If the weeds are too much for you to stand – here are some tips for controlling them How can I control this weed in my lawn? The first step in weed control is to identify the weed and the turf grass. Usually, we can find a herbicide that will kill the weed but not the grass. This information lists common and chemical names for herbicides. Weed killers can come under more than one common name, which mean reading the label is so important. Check the active ingredient to be sure of what you are applying before you use the chemical.
Bahia grass is one of our more persistent weeds. It is a fast growing grass that has 18 inch tall seed heads with a forked seed head on the top. The seed heads show up soon after mowing and make the lawn look uncut. When you walk through the seed heads they will leave a black residue on your leg. Killing one grass (like bahia) out of another grass (our lawn) is difficult at best.
Vantage or Poast (which contain the active ingredient sethoxydim) kill or damage most grasses except centipede and fine fescue (which most of us don’t grow). They kill crabgrass well, but do not work as well on bahia grass. Spray them over centipede to reduce the amount of bahia grass in the turf. This may require several treatments four weeks or so apart. Spray again when the weed recovers and has two inches of new growth.
Results may be only fair even with repeated treatments exactly as the label recommends. Vantage or Poast will probably not completely control bahia grass in centipede lawns. With regular use year after year, they may help to manage this weed. Do not use Poast or Vantage on lawns other than centipede.
Manor (metsulfuron) controls bahia better than Poast or Vantage. It is generally available only to commercial landscape firms. It is fairly expensive. You can spray Manor on Bermuda, zoysia, St. Augustine and centipede lawns.
Repeated spot applications of Round up or Finale should kill weedy grasses like Bermudagrass or bahia.
Be aware, these will also kill any lawn grass they are sprayed on.
Bermudagrass and bahia are very drought tolerant weeds. If they are weed problems in your turf, you may not be able to manage them without a properly operating sprinkler system. Dry weather kills or stunts other grasses and allows Bermudagrass and bahia to spread. Water lawns with one inch of water once a week or one-half to three-quarter inch twice a week during dry weather. The best lawn weed control is thick healthy turf.
I am having problems with nutgrass in my lawn! Use two applications of Image (imazaquin) four to six weeks apart. Image may yellow turf, especially in hot weather. Sedgehammer (halosulfuron) may work better on nutgrass and is less likely to damage turf. It is also harder to locate.
Annual sedges look like grasses but have waxy leaves which emerge three at a time. The seed heads are small and look prickly, though they are not hard like sandspur seed heads. There are often three long leaves just below the seed head. Sedges usually grow where the soil is wet, hard or poorly drained.
Image or Sedgehammer may control some of the annual sedges that crop up in wet or compacted areas of our lawn. There are several types of these sedges and you will not know if the herbicide will kill them until you try. Expect the weed to return unless you correct the problem (wet or hard soil, poor drainage) that caused the problem in the first place.
For information on these or other chemicals, contact the UGA Extension Office. Most herbicides require good plant growing conditions for best control - moist soils and moderate temperatures. Some herbicides will damage grass at high temperatures. Read the label all label directions.
Richard Evans is the Bryan County UGA Extension Coordinator. You can reach the Bryan County Extension Office at uge3029@uga.edu or call (912) 653-2231.