Garden Tips: Manage Bermudagrass in home lawns

There are two main types of grassy weeds in home lawns: annual ones that come up from seed each year and perennial ones that persist from year to year, growing from roots and runners that survive the winter. Controlling grassy perennial weeds is a challenge. There are few, if any, chemicals available that will effectively kill the offending weed without harming desirable grasses.

One of the most hard to control perennial grassy weed is Bermudagrass. Bermudagrass is commonly planted in warmer parts of the country as a lawn and pasture grass. However, in our region, it is considered a nasty aggressive and invasive weed in lawns and gardens. As a warm-season grass, it’s dormant during winter and does not start actively growing until warmer months. It has tough wiry rhizomes (runners beneath the soil) and stolons (runners above the soil). It is sometimes confused with crabgrass because seed heads are similar, but crabgrass is an annual that sprouts from seed each year and does not have tough persistent rhizomes or stolons.

Poor lawn care practices can encourage Bermudagrass. To avoid helping this dastardly weed, do not fertilize during summer’s warmest months. This is the time of year when Bermudagrass is actively growing, and fertilization helps it grow even more. Abstain from frequent shallow watering and don’t mow the grass short. These practices also promote Bermudagrass growth.

However, even the best of lawn care practices will not get rid of an infestation. If you cannot tolerate this weed taking over, consider using herbicides for management. In the past few years, fenoxaprop has been labeled for use by homeowners for suppression of Bermudagrass. Bayer Advanced Bermudagrass Control for Lawns contains fenoxaprop.

It is important to note that suppression is the key word here. Fenoxaprop does not kill Bermudagrass outright, it only slows its growth. As noted on the label, using fenoxaprop involves repeated applications (every four weeks throughout active growth) over one or more years. Late application or missing an application will significantly impair the chemical’s effectiveness. Proper timing of applications should be accompanied with lawn care practices that do not encourage Bermudagrass.

Of course, you could kill the Bermuda grass to start over with a clean slate. However, an application of the nonselective herbicide glyphosate (also known as Roundup, Impede, Knockout and other trade names) is not a silver bullet. Bermudagrass is so tough that it will probably take several applications or more, spaced four weeks apart, to kill this weed. (Glyphosate should be applied when the Bermudagrass is green and actively growing.) Plus, once it appears dead and you till the ground, wait about two weeks to see if it it begins to regrow; then treat again if it does.

Warning: Common Bermudagrass does a good job of producing seed, so even if you kill the existing perennial plants, it leaves behind seed that is viable for two years or more. If you are lucky enough to get Bermuda grass under control, it can easily re-invade the lawn from seed. Always watch for new patches.

This story was originally published March 6, 2016 at 11:50 AM with the headline "Garden Tips: Manage Bermudagrass in home lawns."