Xtremehorticulture

Controlling Bermudagrass Growing in…..

Common bermudagrass stolons creeping from the lawn over a sidewalk. Hybrid bermudagrass is much more restrained in its growth. This is a queston frequently asked, “How do I control bermudagrass in……” so let’s talk about it. The big problem is common bermudagrass. It is spread by seed, underground stems called rhizomes that can grow under the surface of the soil for many feet and re-emerge in a new location. Sort of like “Whack-A-Mole”. You pull it or spray it here only for it to popup over there. Below ground the bermudagrass cannot get the energy it needs from sunlight. It must rely on food supplies sent by the mother plant growing in sunligh OR live off of stored food in its stems. It can also spread by planting, or accidentally planting, any of its stems above or below ground. For instance you can take the above ground growth, cut it up into small pieces, throw it on the ground, water it and it will start a new plant any place these cut up pieces fall. When we WANT it to spread like this, we call are planting by stolons or “stolonizing” the area. The hybrid bermudagrasses, the kind that are nice to grow like on golf courses, is planted exactly this way. The underground stems that spread the mother plant to a new location all by growing underground are called rhizomes. The only difference between the above ground stems (stolons) and the below ground stems (rhizomes) is there location AND their propensity to either grow above or below ground. What you can do to stolons, you can do with rhizomes essentially. So if you cut up a bunch of rhizomes the same way as stolons and spread them on the soil surface, guess what will happen. You got it. You have a new lawn whether you wanted it or not. Hybrid bermudagrass stolon (left) stem and leaves (right) and rhizome (bottom) Question for YOU. What will happen if you rototill a bermudagrass weed area in the hopes of getting rid of it? Answer: You spread it. So how do you get rid of bermudagrass weeds? You exhaust it. You kill it, let it grow a bit, kill it again, let it grow, kill it again, let it grow, kill it again…… In this way you begin to exhaust its stored food supply AND by constantly killing or cutting off its access to sunlight you deny it the ability to put more stored food into its food supply. In the end you exhaust it, weaken it and it dies. You can deny it sunlight by constantly killing top growth back as soon as it gets exposed to that life-giving light a week or so. You can kill the top growth by mechanically whacking it off to soil level or below or killing it to the ground with a poison such as Roundup or even vinegar. Anything that will cause it to die to the ground and not hurt the surrounding environment. The advantage of Roundup is that it is systemic and will travel into the ground a distance and kill somewhere below ground level. To grow back requires more energy and so it will be more effective than just whacking it off or killing the tops. The disadvantage is that it is a weed killer and it may have some adverse side effects. Other chemicals to look at include Poast and Fusilade which are also systemic weed killers and are potentially less damaging to surrounding plants. Nothing wrong with a hoe, shovel and other tools that will help take it to the ground. Regardless, the secret to success will be to stay on top of it and never let it grow back more than a few inches before you knock it down again.

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Controlling Bermudagrass in a Fescue Lawn

Q. I spoke to you about my patch of Bermudagrass at one of your classes. You said that Bermudagrass could be controlled just by letting a fescue lawn shade the soil. Can I really get my Bermudagrass under control simply by mowing higher? Winter fescue lawn with dormant bermudagrass now obvious. Invasion of bermudagrass is because sprinklers cannot irrigate a triangular patch of grass efficiently. Under irrigation = bermudagrass in the hot desert. A. No, you cannot control existing Bermudagrass in a lawn just by letting the fescue grow taller. I think I was misunderstood. Once you have a fescue lawn established, by keeping the soil shaded you will reduce and possibly eliminate Bermudagrass from getting started. This is what I intended to be heard.             Bermudagrass cannot survive in shade. By keeping the soil surface shaded by a healthy lawn, Bermudagrass will be discouraged. Bermudagrass invades a home lawn where lawns are mowed too short or damaged, thus eliminating shade on the soil surface. Typical places where it invades include around sprinkler heads and the edges of the lawn near concrete. Both of these places are where line trimmers are frequently used to keep grass shorter.             It also invades damaged areas due to under irrigation, disease or insects. Once established in the lawn, Bermudagrass is nearly impossible to eliminate without renovating the entire lawn. This would mean fertilizing, watering and mowing the lawn to get it as healthy as possible and then killing it with Roundup.             This is best done in the fall around mid-September to mid-October. About 10 days after the Roundup application or applications, the lawn can be mowed extremely short, power raked until you see bare soil and reseeded directly into the dying or dead lawn.             The key to eliminating the Bermudagrass will be getting a thorough kill with the Roundup before replanting. Spray once, mow in two days and spray again going 90 degrees to the first spray to get good coverage and a better kill.

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