Bent Grass

Asked September 18, 2020, 2:59 PM EDT

We have struggled with Bent Grass infiltrating our lawn (Kentucky Blue Grass) for 40 years. 2 year ago, we had our lawn killed and slit seeded. Last year the grass looked great, but this year patches of Bent grass have returned. Our neighbors' adjoining lawn has it, of course. We are trying to decide what to do. We had an irrigation system put in two years ago also, so we have thousands of dollars invested in this lawn. Is it unrealistic to get rid of the bent grass permanently, especially with the adjoining lawn infected with it. What would you recommend? Laurie Stirling

Eaton County Michigan

1 Response


This management Information is from

Selective removal of bentgrass patches may be accomplished by solarizing the affected area. Clear plastic can be fixed over the affected area for five-to-seven days. The resultant smothering and radiation (heat) will kill all turf under the plastic. The area can be immediately re-seeded.

Control Options:

Option 1: Mechanical Removal - Due to the perennial nature of bentgrass and its well-developed stolon system it is very difficult to remove by mechanical means. Methods include digging up the offending patches, including several inches of soil and replacing with new topsoil and reseeding. However, any stolons that remain can potentially develop into new plants. Another option is solarization. This method uses clear plastic fastened securely to the ground over the bentgrass areas. Be sure to cut the plastic slightly larger than the patches. Leave the plastic in place for 5-7 days in the spring or summer when the weather is nice. The plastic will help trap the heat close to the soil surface and hopefully devitalize the plant material. After removing the plastic you may reseed the area(s). This method can be very effective for creeping bentgrass because the vegetative tissue close to the surface.

Option 2: Non-selective Chemical Removal - Glyphosate. Use a non-selective herbicide that contains glyphosate to kill the patches. Keep in mind that non-selective means that it kills whatever plants it touches. This method will create dead patches that can be re-established. You will need to make at least two applications. Make the second application 14 days after the first. Seven days after the second application you can rough up the area and sow your new grass seed.

Option 3: Selective Chemical Removal - Until recently, none were available. Mesotrione is the only labeled active ingredient for the selective control of bentgrass in other cool-season grasses. As with other selective grass controls, it requires multiple applications per season. The most effective control is achieved from 3-4 applications applied 14- to 21-days apart.

Option 4: Do Nothing - Obviously creeping bentgrass is green and takes a mowing. You may decide after looking at the other options that it is better than bare soil.”

For future prevention of weeds creeping over your property line, a buffer strip of mulch along the line, or a narrow trench dug and then maintained with an edger or string trimmer, can be helpful. Maintenance of the strip or trench will be needed.

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