Tall fescue often presents a significant challenge when it invades desirable lawns like Kentucky bluegrass or fine fescue. This weed variety grows in distinct, undesirable clumps, disrupting the uniform texture of the turf. The primary difficulty in managing this weed is eliminating it without causing widespread damage to the surrounding lawn. Successfully removing these isolated clumps requires a targeted approach, whether through physical extraction or selective chemical intervention. This guide details methods focused on preserving the existing grass while effectively eradicating the invading fescue.
Confirming the Identity of Tall Fescue
Confirming the grass is the unwanted tall fescue ensures the correct treatment is applied. The most noticeable characteristic is its coarse texture and significantly wider leaf blade compared to finer turf grasses like bluegrass. These blades often appear stiffer and a lighter green color, standing out prominently against the uniform backdrop of the lawn. Unlike many desirable lawn grasses that spread laterally, tall fescue maintains a distinctive clumping growth habit. It expands outward from a central point rather than spreading uniformly. The plant also possesses a deep root system, which allows it to remain greener and taller during periods of summer drought when surrounding turf grasses may enter dormancy.
Non-Chemical Removal for Small Areas
For small or isolated infestations, non-chemical methods offer a precise way to remove the weed without impacting the surrounding turf quality. Manual removal is the most direct approach, involving digging out the entire clump. Because tall fescue develops a deep root system, simply pulling the grass will likely leave root fragments behind, leading to re-sprouting. Use a spade or trowel to extract the entire root ball, ensuring all underground plant material is removed from the soil.
Another option involves using solarization or smothering techniques over the individual clumps. Placing black plastic sheeting or a thick layer of heavy organic mulch, such as wood chips, directly over the fescue clump will block sunlight. This process starves the plant, causing it to die over several weeks to a month.
A highly localized, non-selective spot treatment can be achieved using boiling water or concentrated horticultural vinegar. Pouring boiling water directly onto the crown of the plant will scald the tissue and roots, causing the grass to die rapidly. However, these methods will also kill any desirable turf they contact, creating a bare patch. These approaches are best reserved for lawns with only a few scattered clumps, as they require significant labor and immediate repair of the resulting bare soil.
Selective Chemical Control Options
When dealing with a larger number of fescue clumps, selective chemical control provides the most efficient method for eradication while maintaining the surrounding turf. The goal is to use a selective post-emergent herbicide designed to target grasses, such as tall fescue, while leaving desirable lawn grasses unharmed.
One effective active ingredient is fenoxaprop-p-ethyl, a common component in herbicides formulated to control undesirable grasses within established turf. This chemical works by interrupting the metabolic process, effectively stopping the fescue’s growth and leading to plant death. Specialized products containing quinclorac or certain combinations of sulfonylurea herbicides may also be labeled for selective fescue control in specific turf types.
Always check the product label to ensure it is safe for the type of grass established in the lawn, such as Kentucky bluegrass or perennial ryegrass. Applying the wrong product or concentration can lead to widespread damage, defeating the purpose of selective control.
The best time for herbicide application is generally the early fall, when the tall fescue is actively growing and translocating resources down to its root system. This movement allows the herbicide to be carried efficiently throughout the plant, leading to a complete kill of the deep root structure.
Spot spraying, rather than broadcast application, is recommended to minimize the chemical load on the entire lawn and ensure only the target clumps are treated. When spot spraying, mix the herbicide according to the label instructions for the target weed and use a sprayer set to a fine mist to coat the fescue blades. Multiple applications, spaced according to the product’s guidelines, are necessary to completely eradicate the dense clumps. Following all safety precautions, including wearing personal protective equipment and adhering strictly to application rates and temperature restrictions, is necessary to ensure both personal safety and the efficacy of the treatment.
Restoring the Lawn and Preventing Recurrence
After the tall fescue has been removed, the resulting bare patches require immediate attention to prevent new weed establishment and restore the lawn’s uniformity. Before seeding, the soil should be lightly loosened and amended with a thin layer of compost to provide a favorable seedbed. Selecting a high-quality grass seed that matches the existing desirable turf is necessary for seamless integration.
Overseeding should be done at the recommended rate, lightly raking the seed into the top quarter-inch of soil, and keeping the area consistently moist until germination occurs. Proper long-term cultural practices are the best defense against future recurrence.
Maintaining a taller mowing height, typically between three and four inches, encourages deeper roots and shades the soil surface. This shading prevents sunlight from reaching fescue seeds, inhibiting germination. Practicing deep, infrequent watering encourages a robust root system, making desirable grasses more competitive against opportunistic weeds. A fall fertilization schedule promotes dense turf growth, which naturally crowds out new weed seedlings.