White clover is a perennial, broadleaf weed characterized by its trifoliate leaves and mat-forming, prostrate growth habit. As a legume, clover uniquely fixes atmospheric nitrogen into the soil. This allows it to thrive in nutrient-poor conditions where turfgrass struggles, often compromising the uniform appearance of a traditional lawn.
Manual and Cultural Removal Techniques
Physical removal is a direct option for managing smaller infestations. Hand-pulling is most effective when the soil is moist, allowing the entire root system, including the creeping above-ground stems called stolons, to be removed completely. If any part of the root or stem remains, the clover can easily regrow.
Larger, dense patches of clover can be eliminated through solarization or smothering. This technique involves covering the affected area with black plastic sheeting or a tarp for two to three weeks. Blocking sunlight effectively kills the plant by depriving it of resources needed for growth. Care must be taken, as any surrounding turfgrass under the covering will also die.
Some gardeners use concentrated household substances for spot treatment, such as a solution of white vinegar and dish soap. The vinegar acts as a contact herbicide, burning the clover foliage, while the dish soap helps the solution adhere to the waxy leaf surface. This method is temporary, however, as it often fails to kill the deep roots and may require repeated applications to fully exhaust the perennial plant. Another cultural strategy involves the use of corn gluten meal, which acts as a pre-emergent by inhibiting root formation in germinating seeds.
Targeted Chemical Control Options
When clover infestations are widespread, selective chemical control is the fastest method for eradication. Since clover is a broadleaf plant, it requires a selective post-emergent herbicide that targets broadleaf weeds while leaving turfgrass unharmed. Clover is particularly susceptible to herbicides containing synthetic auxins, which mimic plant hormones.
Effective residential products often contain a mixture of ingredients like 2,4-D, MCPP (mecoprop), and Dicamba, which work together to cause uncontrolled growth that kills the weed. Dicamba is noted for its effectiveness against stubborn broadleaf weeds, including clover. The best time to apply these products is during the clover’s active growth period in the spring or fall when temperatures are moderate.
Application should be targeted, using a coarse spray to ensure the product adheres to the clover foliage and minimize drift onto non-target plants. Always wear appropriate safety gear and strictly follow the manufacturer’s directions regarding mixing ratios and application rates. Reviewing the label ensures the product is safe for the specific type of turfgrass present in the lawn.
Long-Term Lawn Management for Prevention
Clover is considered an indicator plant, signaling that the soil is likely deficient in nitrogen, a nutrient essential for healthy turfgrass growth. Addressing the underlying conditions that allowed clover to thrive is necessary for long-term prevention.
A regular, nitrogen-rich fertilization program should be implemented to promote dense turf. Performing a soil test is recommended to determine specific nutrient deficiencies and pH levels, as turfgrass prefers a pH between 6.0 and 7.0. A strong, healthy lawn is the best defense, as thick grass crowds out weeds and prevents clover seeds from germinating.
Adjusting mowing practices is another crucial preventative measure, as cutting the grass too short stresses the turf and gives prostrate-growing clover a competitive edge. Raising the mower deck to a height of three to four inches encourages taller grass blades, which shade the soil and inhibit the germination of clover seeds. Taller grass also develops deeper, more resilient root systems.
The method of watering influences turf health; deep, infrequent watering encourages turf roots to grow downward, while shallow, frequent watering favors the shallow root systems of weeds like clover. Additionally, addressing soil compaction through core aeration allows water, air, and nutrients to penetrate the soil. This supports robust turf growth that naturally excludes clover.