Tall fescue, when not the intended turfgrass, appears as coarse clumps that disrupt the visual uniformity of a lawn. These perennial grasses have a wider blade width, a stiffer texture, and often a distinctly different color and vertical growth rate than fine turf species like Kentucky bluegrass or fine fescues. Because tall fescue is a bunch-type grass, it does not spread laterally, leading to dense, isolated clumps that can become large and difficult to mow. Removing these unwanted patches and restoring a smooth, consistent lawn requires careful planning and a multi-step approach of removal.
Manual and Non-Chemical Removal
For homeowners who prefer to avoid herbicides or who have only a few isolated clumps, physical removal is a direct and effective option. The deep root system of tall fescue, which can extend two to three feet deep, necessitates thorough digging to ensure the entire plant is removed. Before digging, deeply watering the area can help to loosen the soil, making it easier to extract the entire root mass without leaving fragments that could regrow. Use a sharp spade or trowel to cut around the circumference of the clump, going deep enough to sever the root structure.
A non-chemical method for larger patches is solarization, which uses heat and light deprivation to kill the grass. This involves covering the fescue patch with an opaque material, like black plastic sheeting or thick cardboard, to block all sunlight from reaching the leaves. The lack of light prevents photosynthesis, while the material traps heat, effectively cooking the grass over several weeks. For a complete kill, the material should remain in place for at least four to six weeks during the warmest part of the year.
Chemical Spot Treatment Strategies
When dealing with many clumps, chemical spot treatment using a non-selective herbicide is often the most practical solution. This requires a product containing glyphosate, which is absorbed by the foliage and translocated throughout the plant, killing the entire root system. Since glyphosate is non-selective, it will kill any green plant material it contacts, including the desirable turfgrass surrounding the fescue clump.
Selective herbicides are ineffective against established tall fescue clumps, making the non-selective approach necessary. Application must be precise to minimize damage to the surrounding lawn; a small pump sprayer with a narrow spray pattern or even carefully painting the herbicide onto the fescue leaves can limit overspray. For the chemical to work, the tall fescue must be actively growing, meaning treatment is best done during the cooler seasons of spring or fall. Always use protective equipment and wait the specified time on the product label before disturbing the treated area.
Repairing Bare Spots and Preventing Reoccurrence
After the tall fescue has been killed, the resulting bare area must be prepared for new seeding. Rake out the dead grass and loosen the soil surface with a rake or hand cultivator to ensure good seed-to-soil contact. Amending the area with a thin layer of topsoil or compost can enrich the seedbed and promote quicker establishment.
The next step is to reseed the spot with the same type of turfgrass, following the recommended seeding rate. After seeding, gently rake the seed into the top quarter-inch of soil and cover it lightly with a material like peat moss or straw to help retain moisture. Consistent, light watering—keeping the top inch of soil continuously moist—is necessary until the new seedlings are well-established.
For long-term prevention, maintain a healthy, dense lawn by mowing at a higher height, generally between three and four inches, which shades the soil and reduces the ability of new fescue seeds to germinate. Regular overseeding, combined with a fertilization schedule, will increase the turf density, making it difficult for invasive perennial grasses to take hold.