White clover (Trifolium repens) is a perennial broadleaf plant that commonly appears as a weed in turfgrass. Its presence often signals that the underlying soil lacks the nutrients necessary for a healthy lawn. As a legume, clover hosts Rhizobium bacteria in its root nodules, which draw nitrogen from the atmosphere and convert it into a usable form. This ability allows it to flourish in nitrogen-deficient soil where turfgrass struggles to compete. Successfully removing clover involves a two-part strategy: immediate removal and long-term cultural changes to improve turf health.
Non-Chemical Removal Methods
For small, isolated patches of clover, manual removal is an effective and environmentally friendly option. This method works best after rain or watering, as damp soil makes it easier to extract the entire root system. Ensure you pull up the entire root and the creeping stems, called stolons, which root at the nodes and allow the plant to spread rapidly across the soil surface.
Smothering is a practical approach for larger, dense clover patches too extensive for hand-pulling. Cover the affected area with a light-blocking material, such as black plastic sheeting or thick layers of newspaper. This technique starves the clover of the sunlight needed for photosynthesis, effectively killing the plants underneath. The material should remain in place for several weeks to ensure the patch is eliminated before reseeding.
A concentrated vinegar solution can also be used as a targeted spot treatment, though caution is advised as it is a non-selective contact herbicide. Household white vinegar, which contains about 5% acetic acid, is usually too weak for effective control. Instead, you would need a horticultural vinegar with an acetic acid concentration closer to 20% to 30%. Adding a small amount of dish soap helps the solution adhere to the clover’s waxy leaves, increasing its efficacy. This solution will likely scorch any turfgrass it contacts, so spray only the clover leaves and avoid surrounding healthy grass.
Selecting and Applying Herbicides
When clover is widespread and non-chemical methods are impractical, selective broadleaf herbicides offer reliable control. These products are formulated to target broadleaf weeds like clover while leaving turfgrass unharmed. Effective clover control products typically contain a combination of active ingredients, such as 2,4-D, MCPP (mecoprop-p), and dicamba.
These systemic herbicides mimic natural plant growth hormones, causing the clover to grow in an uncontrolled, unsustainable manner that leads to its eventual death. The timing of application is a significant factor in the success of chemical control. The most effective time to apply these products is in the fall, generally from mid-September through early November, when the clover is actively moving sugars and nutrients down to its roots in preparation for winter.
Applying the herbicide during this period ensures the systemic chemical is carried deep into the root structure, resulting in more complete eradication. For best results, avoid mowing the lawn for two to three days before and after application to allow sufficient leaf surface area for absorption and time for the product to translocate throughout the plant. Granular forms of herbicide should be applied when the foliage is wet with dew so the particles stick to the leaves. Liquid sprays require a 24-hour period without rain or irrigation to prevent them from being washed away.
Adjusting Lawn Conditions for Prevention
The most sustainable way to eliminate clover is to address the underlying soil conditions that allowed it to thrive. Since clover uses its nitrogen-fixing ability to gain a competitive advantage in nutrient-poor conditions, the primary prevention strategy involves consistent nitrogen management. Regular fertilization with a nitrogen-rich product encourages the turfgrass to become dense and vigorous, making the environment hostile to clover establishment.
A professional soil test can provide specific recommendations for nitrogen, phosphorus, and potassium levels, as well as the soil’s pH. Turfgrass prefers a slightly acidic to neutral pH, typically between 6.0 and 7.0. Correcting the pH can significantly improve grass health, and a healthy lawn forms a thick canopy that blocks the sunlight clover seeds need to germinate.
Proper mowing height creates a dense turf layer hostile to weeds. Raising your mower deck to at least three inches allows the grass blades to shade the soil. This shading naturally suppresses clover seed germination and keeps the soil cooler, which favors turf health. Cutting the grass too short stresses the turf and exposes the soil, creating an ideal environment for weeds to take hold.
Watering practices promote deep turf roots that can outcompete clover. The most beneficial technique is deep and infrequent watering, providing about one inch of water once or twice a week, rather than short, daily sprinkles. Shallow watering encourages shallow turf roots and favors weeds like clover. Deep watering encourages the grass to develop extensive root systems capable of accessing water and nutrients deeper in the soil profile.
Ensuring good soil structure through aeration and overseeding helps maintain a dense, competitive lawn. Clover is tolerant of compacted soil, where turfgrass roots struggle to penetrate and access resources. Annual or bi-annual core aeration alleviates compaction, allowing grass roots to grow deeper and improving the movement of air and water. Overseeding thin patches further thickens the turf, eliminating the open spaces where clover can easily establish.