Triclopyr is a selective post-emergent herbicide commonly used to manage broadleaf weeds and woody plants, especially in turfgrass and non-crop areas. For anyone battling a clover infestation in their lawn, Triclopyr is one of the most effective chemical tools available for eliminating both white and red clover. This article explains how this herbicide works, the best ways to apply it, what plants it safely spares, and the necessary safety measures for its use.
How Triclopyr Targets Clover
Triclopyr is highly effective against clover because it functions as a synthetic auxin, which is a class of plant growth regulators. This herbicide is absorbed systemically through the clover’s leaves and rapidly transported throughout the entire plant, including the roots and growing points. Once inside, the chemical mimics the plant’s natural growth hormone, auxin, but at an extremely high and unregulated concentration.
The overwhelming presence of this false growth signal causes the clover to suffer from abnormal and uncontrolled growth. This fatal growth disruption often presents as twisted stems and deformed leaves before the plant ultimately dies, typically within two to three weeks. The systemic nature of Triclopyr is especially important for controlling aggressive weeds like clover because it ensures the entire root system is targeted, preventing regrowth that can occur with non-systemic products.
Proper Application Techniques and Timing
Proper application technique and timing are important when treating clover with Triclopyr. The herbicide should be applied when clover plants are actively growing, which typically occurs during the spring and fall seasons. Applying during periods of active growth allows the plant to readily absorb and transport the chemical throughout its system for maximum efficacy.
The application should be done when temperatures are moderate, generally avoiding application when the air temperature exceeds 85°F to 90°F to prevent injury to the desirable turfgrass. It is also important to ensure no rainfall is expected for at least 4 to 24 hours after application so the herbicide has sufficient time to be absorbed by the clover leaves. Many professional applicators also recommend delaying mowing the lawn for two days before and two days after treatment to ensure maximum leaf surface is available to absorb the chemical.
Clover leaves have a waxy surface that can cause liquid herbicide to bead up and roll off. Therefore, a non-ionic surfactant is often necessary, as it helps the Triclopyr solution stick to the clover foliage and penetrate the leaf’s protective layer. For precise control, spot treatments may be preferable for smaller clover patches, while larger infestations may require a broadcast application across the entire lawn. Always follow the specific mixing ratios and application rates listed on the product label, as these can vary between different formulations.
Selectivity: What Triclopyr Spares
Triclopyr is classified as a selective herbicide because it primarily targets broadleaf plants while sparing most turfgrasses. This selectivity means the herbicide can be safely applied to lawns containing common cool-season turf varieties such as fescue, Kentucky bluegrass, and perennial ryegrass. Warm-season grasses like Zoysia and Bermuda grass are also generally tolerant of Triclopyr applications when used according to label instructions.
Beyond clover, Triclopyr is also highly effective against other hard-to-control broadleaf weeds in turf, including ground ivy, wild violet, oxalis (woodsorrel), and black medic. The grasses are not significantly affected because their different physiological structure allows them to process and break down the chemical before the uncontrolled growth effects can become fatal.
Handling and Safety Guidelines
Handling Triclopyr safely requires adherence to specific guidelines to protect the user, pets, and the environment. Before mixing or applying the product, Personal Protective Equipment (PPE) is required, including long-sleeved shirts, long pants, socks, shoes, protective eyewear, and chemical-resistant gloves. Washing hands thoroughly after handling the product and before eating or drinking is also necessary.
Restricted Entry Interval
For the safety of children and pets, a Restricted Entry Interval (REI) must be observed, meaning they should not enter the treated area until the spray has completely dried. Depending on the specific product and its concentration, this interval can range from a few hours up to 24 to 48 hours for some commercial applications.
Environmental Safety and Storage
Care must also be taken to avoid overspray or runoff into water sources, such as ponds or streams, as the herbicide can be toxic to aquatic life. Unused product should be stored securely in its original container, away from food and feed, and disposed of according to local regulations and the instructions on the product label.