Triclopyr Ester is primarily a selective, systemic herbicide used to control broadleaf weeds, woody plants, and brush without harming most turfgrasses. It is absorbed by the plant’s leaves and roots, where it mimics the growth hormone auxin. This causes uncontrolled cell division and growth abnormalities, leading to the destruction of the target plant’s vascular tissue. Its oil-soluble nature makes it particularly effective for penetrating the waxy cuticles of brush and woody stems, making it popular for non-crop areas and turf maintenance.
Understanding Product Concentration
The amount of Triclopyr Ester used per gallon varies because commercial products differ significantly in their concentration of the active ingredient (AI). Products are formulated with different percentages of Triclopyr Butoxyethyl Ester (BEE). A common commercial concentration is 61.6% AI, but the label instructions correspond directly to that specific concentration.
Triclopyr comes in two main forms: the Ester and the Amine salt, and it is crucial to confirm the use of the Ester formulation for woody control applications. The Ester formulation is oil-soluble, which allows for better absorption into tough, woody plants, and is preferred for basal bark or cut stump treatments. The Amine formulation is water-soluble and generally used in turf settings where volatility is a major concern, as it is less prone to vapor drift.
Determining the Correct Mixing Ratio
These mixing ratios are based on a standard 61.6% Triclopyr Ester concentration, common in many consumer and professional products. The required amount of herbicide per gallon changes dramatically based on the application method and the type of vegetation targeted. Always consult the specific product’s label for the final mixing instructions.
Turf Broadcast Spraying
For standard broadcast spraying on ornamental turf, the rate is relatively low to prevent injury to desirable grasses. This application requires mixing 3/8 to 3/4 fluid ounces of the 61.6% concentrate per 1,000 square feet. The water used to dilute this concentrate, such as one gallon, is simply the carrier volume needed to ensure uniform coverage.
Spot Treatments
When performing spot treatments on individual broadleaf weeds, a higher concentration is used to ensure maximum absorption. A common recommendation is to mix 1 1/4 to 2 fluid ounces of concentrate into one gallon of total spray mixture. This creates a potent 1.0% to 1.5% solution effective for controlling tough weeds like ground ivy or ragweed.
Woody Brush and Stump Treatments
For controlling woody brush, vines, or performing cut stump treatments, the concentration increases substantially. A general guideline for a foliar spray on heavy brush is to mix 4 to 8 fluid ounces of concentrate in one gallon of water. For cut stump or basal bark treatments, the product may be used undiluted or in a highly concentrated oil-based solution, depending on the label.
Application Techniques and Safety Measures
Effective application requires thorough and uniform coverage of the target foliage without excessive runoff. The best time to apply Triclopyr Ester is during warm weather, when weeds and brush are actively growing, as systemic action depends on the plant’s metabolism. Applying to dry foliage is recommended, and avoid watering the treated area for at least 24 hours to allow for proper absorption.
Drift prevention is a serious consideration, especially with the volatile Ester form, which can vaporize at high temperatures and harm sensitive plants nearby. Using low-pressure sprayers and avoiding application on windy days helps minimize the risk of off-target injury. Cut stump and basal treatments, which involve minimal drift risk, can be performed year-round.
Handling this concentrated chemical requires mandatory Personal Protective Equipment (PPE) to minimize exposure. Applicators must wear long-sleeved shirts, long pants, and chemical-resistant gloves, such as those made from nitrile rubber or neoprene. Protective eyewear is also necessary to prevent contact with the chemical, as it can cause moderate eye irritation. After application, contaminated clothing should be removed immediately, and hands washed thoroughly before eating, drinking, or using the restroom.