Chemicals offer an effective method for removing unwanted trees, whether they are invasive species, hazardous growth, or stumps preventing future landscaping. Using a chemical agent ensures the entire root system is killed, preventing resprouting that occurs when a tree is merely cut down. This approach is useful for eliminating stumps without the need for mechanical grinding. The goal is to introduce a systemic chemical directly into the plant’s vascular system, allowing the tree to distribute the active ingredient throughout its roots for complete control.
Effective Systemic Herbicides
Killing a woody plant requires a systemic herbicide, meaning the chemical is absorbed and moves through the tree’s vascular system to reach the furthest root tips. The two most effective active ingredients widely available are glyphosate and triclopyr. Both chemicals must be used in a highly concentrated form, often undiluted or mixed to a concentration greater than 20% for glyphosate and over 8% for triclopyr, to be effective against dense woody tissue.
Glyphosate is a non-selective, broad-spectrum herbicide that works by inhibiting the shikimate pathway, an enzyme pathway found only in plants. This pathway is necessary for the plant to synthesize three aromatic amino acids: tyrosine, tryptophan, and phenylalanine. Preventing the production of these building blocks starves the plant of necessary proteins, leading to a slow decline. This herbicide has minimal soil activity, meaning it binds quickly to soil particles and is deactivated, reducing the risk of harm to surrounding plants through root uptake.
Triclopyr is a selective herbicide that primarily targets broadleaf and woody plants while leaving grasses unharmed. This chemical acts as a synthetic auxin, mimicking and overloading the tree’s natural growth hormones. The resulting uncontrolled, rapid, and abnormal growth caused by this hormonal disruption leads to the death of the tree. Triclopyr is available in two forms: an amine salt (water-soluble) and an ester (oil-soluble), with the oil-soluble ester formulation being useful for basal bark applications on standing trees.
The most effective time to apply these systemic chemicals is in the late summer or fall, just before leaf color change, or during the dormant season. During autumn, the tree naturally moves its resources, or photosynthates, downward into the roots for winter storage. Applying the herbicide at this time allows it to be efficiently transported along with the plant’s stored energy directly into the root system.
Targeted Application Techniques
Successful tree removal relies on placing the concentrated herbicide directly into the living tissue of the tree: the cambium layer and the adjacent sapwood. For a freshly cut stump, the Cut-Stump Treatment is the simplest and most common method. The tree must be cut close to the ground, and the herbicide must be applied immediately, ideally within 5 to 15 minutes, before the cut surface begins to dry and the vascular system seals itself.
The application should focus specifically on the cambium layer, the thin, active ring just beneath the bark. For stumps larger than three inches in diameter, only the outer two inches of the stump face should be treated. The inner heartwood is dead and will not transport the chemical. Treating the outer ring ensures the chemical is absorbed by the phloem and xylem, the main transport tissues that move nutrients and water throughout the tree.
For standing trees, the Frill or Girdle Application, also known as “hack-and-squirt,” is an effective technique. This involves using a hatchet or axe to make a series of downward-angled cuts, or “frills,” completely around the circumference of the trunk at a comfortable working height. The cuts should penetrate through the bark and cambium layer and slightly into the sapwood.
These cuts should be made close together, typically one cut for every two to three inches of the tree’s diameter, ensuring the cuts overlap slightly to create a continuous path around the trunk. Immediately after each cut is made, a small, measured amount of the concentrated herbicide is squirted into the pocket created by the downward angle. This method directly injects the chemical into the sap stream, maximizing uptake while minimizing environmental exposure.
Alternatively, the Drill-and-Fill Method is used for standing trees, particularly those with thicker bark that may be difficult to frill cleanly. Using a drill bit, bore holes into the trunk at a downward angle of about 45 degrees, positioning the holes as low to the ground as possible. The holes should be spaced approximately three inches apart around the entire base of the tree, reaching the sapwood. The concentrated chemical is then immediately injected into each hole, filling it entirely. The downward angle helps prevent the herbicide from running out, and immediate application utilizes the tree’s active transport mechanism before it can seal the wound.
Safety and Environmental Precautions
Working with concentrated systemic herbicides requires strict adherence to safety protocols to protect both the user and the surrounding environment. Personal protective equipment (PPE) is mandatory, including chemical-resistant, unlined gloves, long-sleeved shirts, long pants, and protective eyewear, especially when handling concentrates. Always use the original container and never transfer the chemical to a food or beverage container, as this poses a poisoning risk.
To prevent harm to non-target plants, use targeted methods like cut-stump, frill, or drill-and-fill, as these reduce the risk of spray drift or overspray. When choosing a product, select water-soluble formulations, such as glyphosate or triclopyr amine, for residential areas because they have little residual soil activity. Avoid herbicides with high soil mobility, such as imazapyr, which can be absorbed by the roots of nearby desirable trees and cause unintended damage.
For proper storage, keep all concentrated chemicals sealed in their original, labeled containers and store them in a cool, dry, well-ventilated area that is securely locked and out of reach of children and pets. The storage area should be kept away from food, animal feed, and ignition sources. When disposing of containers, triple-rinse empty plastic containers with water, pouring the rinse water into the application site, and then puncture the container before placing it in the trash. Never pour unused or leftover herbicides down a drain or into the garbage; instead, contact your local solid waste authority for safe disposal.