White clover (Trifolium repens) is a common broadleaf weed often appearing in lawns, recognized by its three leaflets and low-growing, mat-forming habit. Homeowners often seek methods to eliminate this plant without damaging existing turfgrass. The solution involves a selective approach, using chemical controls or cultural practices that specifically target the clover while leaving the narrow-leaf grass unharmed.
Identifying Selective Chemical Controls
The direct answer to killing white clover without harming grass involves using selective broadleaf herbicides. These products work because they contain active ingredients that target dicots (broadleaf plants like clover) while sparing monocots (which include all turfgrasses). The most common and effective active ingredients are 2,4-D, MCPP (mecoprop), Dicamba, and Triclopyr.
These compounds function as synthetic auxins, mimicking natural plant growth hormones but delivering an overwhelming dose to the clover. This excessive exposure causes uncontrolled, rapid growth, leading to deformed leaves and stem twisting. Because turfgrasses metabolize these synthetic hormones differently, they are largely unaffected at recommended rates. Most commercial products combine two or three of these ingredients to create a potent “three-way” formulation that controls a wide spectrum of broadleaf weeds, including clover.
Best Practices for Herbicide Application
The most effective time to treat white clover is when it is actively growing, typically in the spring or early summer, or during a fall application, which often yields the best control. Applying the product when temperatures are consistently below 90°F is important, as high heat can cause the chemical to volatilize and drift, potentially damaging non-target plants.
For application, concentrate products must be mixed precisely according to the label’s dilution instructions. It is beneficial to include a non-ionic surfactant in the tank mix, which helps the herbicide adhere better to the waxy surface of the clover leaves. Spot treating isolated patches is generally recommended over a broadcast application to minimize the overall use of chemicals.
A hand-held pump sprayer with a fan nozzle setting allows for accurate coverage of the clover foliage. Always wear personal protective equipment (PPE), including a long-sleeved shirt, long pants, chemical-resistant gloves, socks, and closed-toe shoes when handling these products. Following the manufacturer’s label directions for mixing, application rate, and safety is the most important step for effective control.
Non-Chemical and Cultural Management
For immediate, small-scale control without synthetic chemicals, manual removal is a practical option. White clover is a perennial, so it is necessary to pull the entire root system to prevent regrowth. Pulling the plants after a rainfall or deep watering makes removal easier, as the moist soil releases the roots more readily.
Cultural practices, particularly mowing, can also be used to stress the clover patches. Mowing the turfgrass at a high setting (typically two to four inches) encourages the grass blades to shade the soil surface. This shading prevents the sun-loving clover from germinating and limits the growth of existing patches. Another non-chemical method for dense patches is solarization, which involves covering the area with a clear plastic tarp for several weeks to superheat the soil and eliminate the clover and its seed bank.
Long-Term Lawn Health and Prevention
The most effective long-term defense against white clover is maintaining a dense, healthy stand of turfgrass. Clover is a legume that can fix its own nitrogen, allowing it to thrive in nutrient-poor soils where grass struggles. Applying nitrogen-rich fertilizer regularly promotes aggressive grass growth, which outcompetes and naturally shades the clover.
A soil test can determine the current pH level and nutrient deficiencies, guiding the fertilization program. Most lawn grasses prefer a soil pH between 6.5 and 7.0; adjusting the pH to this optimal range favors the turfgrass over the clover. Overseeding with robust turfgrass varieties, such as turf-type tall fescue or Kentucky bluegrass, increases the lawn’s density. A thick lawn canopy is the best natural barrier, physically crowding out white clover seeds.