Question:
How do I control tall fescue in my lawn?Answer:
Tall fescue is a cool-season perennial grass occasionally present in Iowa lawns. Because it has good drought, heat, and foot-traffic tolerance, the narrow-leaf varieties (sometimes called turf-type) can be a welcome addition to the traditional Iowa cool-season lawn comprised primarily of Kentucky bluegrass. However, common tall fescue (also called forage type) has a wide leaf blade that does not blend well with other turfgrasses. Its clump-forming nature and coarse texture can make it an unattractive addition to the lawn for some gardeners.
Perennial grasses, such as tall fescue, are some of the most difficult to control weeds in the lawn. Control is difficult because there are very few herbicides available to homeowners that will selectively destroy these weeds and hand digging is often difficult and time consuming.
Pulling & Digging
While pulling or digging other weedy perennial grasses, like nimblewill or quackgrass, is difficult, the clumping nature of tall fescue makes it a more viable option. To be successful, the entire plant and root system must be removed. Any remaining root fragments or plant pieces will resprout and grow. This method is best accomplished after a soaking rain or deep watering.
Management utilizing hand pulling and digging requires persistence to be effective. Rarely will one round of weed removal fully eradicate tall fescue from the entire lawn.
Fill any divots left behind with soil and seed or sod the areas with a desirable grass.
Herbicides
When infestations are large, the most effective control method is often with herbicides utilizing a nonselective herbicide like glyphosate (Roundup®). Nonselective herbicides kill virtually all plants to which the material is applied (desirable and weedy), so it must be applied carefully and only to the weedy grass species.
Apply the herbicide while plants are actively growing (typically when temperatures are above 50°F). The most effective time to apply herbicides to control tall fescue is in the fall before the first frost. Spray the weedy patches as well as a few inches beyond these areas to ensure their complete destruction. A second application is necessary if the treated areas are not dead in 2 to 4 weeks.
After the treated areas have been completely destroyed, reestablish the lawn by seeding or sodding.
Digging & Herbicides
Utilizing both control techniques can also yield good results. Dig and remove as much of the undesirable grass as possible, as outlined above. Then, wait several weeks to see what regrows. Treat the regrowth with a herbicide as outlined above. This method can allow you to get good control utilizing less herbicide.