White clover (Trifolium repens) is a perennial, low-growing legume often found spreading across lawns, recognizable by its characteristic three leaflets and small white flowers. This plant is a nitrogen fixer, meaning it partners with Rhizobium bacteria to convert atmospheric nitrogen into a usable form within its root nodules, allowing it to thrive in nutrient-poor soils where turfgrass often struggles. Clover’s ability to establish colonies rapidly via above-ground stems called stolons makes it a persistent weed. Successfully removing clover requires a dual approach: first, immediate eradication of existing patches, and second, long-term cultural practices to improve lawn health and prevent its return.
Killing Clover with Natural and Physical Methods
For smaller infestations or for those avoiding synthetic chemicals, physical removal and natural treatments offer immediate solutions. The most direct method is hand-pulling, which is most effective when the soil is moist, such as after rainfall or watering. When pulling, it is important to remove the entire stolon and the root system to prevent the plant from regenerating.
Another immediate approach is to smother small to medium-sized patches by depriving the clover of the sunlight it needs to survive. This can be achieved by covering the area with opaque plastic sheeting or cardboard for several weeks. Because this method is non-selective, it will also kill the underlying turfgrass, requiring reseeding after the clover has died.
Vinegar and dish soap solutions are sometimes used as a natural contact herbicide. The acetic acid in horticultural-grade vinegar rapidly dehydrates the plant’s foliage. Dish soap acts as a surfactant, helping the acidic mixture adhere to the clover leaves. Vinegar is a non-selective treatment that will damage turfgrass upon contact, and since it usually does not kill the deep root system, repeat applications are often necessary.
Using corn gluten meal offers a gentler, preventative approach. It is a pre-emergent herbicide that works by inhibiting root formation in germinating seeds. Applying it before seeds germinate in the spring and fall can help reduce future clover populations, though it will not kill established clover. Corn gluten meal also acts as a slow-release nitrogen fertilizer, which helps the turfgrass become denser and better able to outcompete weeds.
Selective Herbicides for Clover Eradication
For widespread or stubborn clover infestations, selective broadleaf herbicides provide the most effective and fastest eradication method. These products are formulated to target broadleaf weeds, such as Trifolium repens, while leaving common turfgrasses unharmed. The most effective herbicides for clover contain a combination of active ingredients, often referred to as a three-way mixture.
Look for products containing ingredients like 2,4-D, Mecoprop-p (MCPP), and Dicamba. The combination ensures a systemic kill, meaning the herbicide is absorbed by the foliage and translocated throughout the plant, including the stolons and roots. This systemic action is necessary because clover’s dense, creeping growth habit makes surface-level treatments insufficient.
Timing is an important factor in maximizing herbicide effectiveness, with application windows in the spring and fall yielding the best results. Clover is most susceptible when it is actively growing, typically when temperatures are between 50 and 85 degrees Fahrenheit. Avoid applying herbicides during periods of extreme heat or drought, as the plant’s growth slows, reducing chemical absorption.
Proper application technique ensures success and minimizes damage to the lawn. For small, isolated patches of clover, a spot treatment is preferable to minimize chemical use across the entire yard. Wait at least two days after mowing before application, as this allows the clover leaves to regrow slightly, maximizing the surface area for herbicide absorption. Always follow the specific mixing and application rates detailed on the product label, as using too much can injure the turf, while using too little will be ineffective.
Long-Term Lawn Care to Prevent Clover Return
Eradicating existing clover is only the first step; preventing its return requires cultural practices that improve the turf’s health and density. Clover thrives in lawns with low nitrogen levels, giving it a distinct competitive advantage over grass since it can fix its own nitrogen. The strategy involves regular fertilization with a high-nitrogen product, which encourages vigorous grass growth that naturally crowds out the clover.
Adjusting your mowing practices is a simple and highly effective preventative measure. Raising the mower blade to a height of three to four inches promotes taller, denser turf, which shades the soil surface. This shading action blocks the sunlight necessary for clover seeds to germinate and establish themselves. Leaving grass clippings on the lawn also helps, as they decompose and cycle nitrogen back into the soil, further discouraging clover.
Addressing soil health is another important component, particularly by managing compaction. Clover can tolerate compacted soil better than many turfgrasses, so regular aeration helps the grass establish deeper, stronger roots. Aeration improves the movement of water, air, and nutrients, creating an environment where healthy turf can outcompete the weed.
Finally, adopting deep, infrequent watering practices encourages the grass to develop a robust, deep root system. Clover, which has a relatively shallow root system, struggles in drier conditions when competing with deeply rooted turf. Watering deeply every few days, rather than lightly every day, trains the grass roots to seek moisture deeper in the soil, strengthening the lawn’s overall resilience.