The roots and stump remaining after a bush is removed present a significant problem, as the root system often retains enough energy to send up new, unwanted sprouts. These persistent roots can also become obstructions in the soil, interfering with future planting or hardscaping. To permanently stop regrowth, you must completely kill the remaining root system. This requires applying a killing agent directly to the stump tissue, ensuring the substance is translocated down to the furthest root tips.
Preparing the Stump for Treatment
The success of any root-killing method depends heavily on how well the stump is prepared to absorb the treatment. Begin by cutting the bush trunk as close to the ground as possible, ideally leaving a stump no more than one to two inches high. Trimming the stump low minimizes the remaining woody material and reduces the visual impact as the stump begins to decay. Removing loose debris or bark from the cut surface is important to ensure the treatment directly contacts the underlying wood tissue.
The most effective way to maximize absorption is by drilling holes into the freshly cut stump face. Using the widest and deepest drill bit available, create holes spaced roughly three to four inches apart, boring down several inches into the wood. The holes should be drilled at a slight downward angle, which helps to contain the liquid or granular treatment and directs it inward towards the heartwood and cambium layer. This physical preparation creates channels for the killing agent to travel deep into the root system.
Chemical Methods for Root Elimination
Chemical treatment is often the fastest and most reliable way to eliminate a stubborn root system and prevent regrowth. This method relies on systemic herbicides, which are absorbed by the stump and translocated through the plant’s vascular system to kill the entire root mass. The most effective active ingredients for this purpose are glyphosate and triclopyr, which should be applied immediately after the stump is cut.
For woody plants, a concentrated solution of glyphosate (often mixed to a 50% concentration with water) or an undiluted triclopyr product is recommended. The herbicide must be applied directly to the living tissue, known as the cambium layer—the narrow band of lighter-colored wood just inside the bark. This outer ring transports the chemical down to the roots, so concentrating the application here is crucial. For smaller bush stumps less than four inches in diameter, the entire cut surface should be saturated with the herbicide.
The best results occur when the bush is actively moving resources downward to its roots, typically in late summer or fall. Water-soluble formulations of glyphosate require application within minutes of cutting, as the stump surface quickly forms a seal, preventing absorption. If treatment is delayed, an oil-soluble triclopyr ester product mixed with a basal oil is a better option, as it can penetrate dried wood more effectively. Using a paintbrush or a low-pressure sprayer ensures precise placement into the prepared holes and cambium layer, preventing runoff.
Non-Chemical and Natural Root Removal
Non-chemical methods utilize physical removal or substances that accelerate decomposition for those who prefer to avoid synthetic herbicides. The most immediate non-chemical option is mechanical removal, using a stump grinder to shred the wood several inches below the soil line. For smaller bushes, major roots can be exposed by digging around the stump and severing them with a mattock or axe before physically pulling the remaining root ball out of the ground.
Natural agents like rock salt or Epsom salt can be used to kill the stump tissue through dehydration. Epsom salt (magnesium sulfate) is hygroscopic, drawing moisture out of the living wood cells when packed into the drilled holes. This desiccation stops the flow of nutrients and prevents the stump from resprouting, though the process of decay can take several months to a year. Rock salt (sodium chloride) works through a similar mechanism of dehydration and is effective at killing the stump, but it carries a greater risk of sterilizing the surrounding soil.
Decay can be accelerated using a high-nitrogen fertilizer, which feeds the fungi and microorganisms responsible for wood decomposition. A granular fertilizer with a high first number in its NPK ratio (like 45-0-0) should be poured into the stump holes and then saturated with water.
Covering the treated stump with a plastic tarp or mulch helps to retain moisture and warmth, creating an ideal environment for the decay organisms to thrive. This decay-acceleration process is slower than chemical methods, often taking six months to a few years to fully break down the stump enough for easy removal.
Protecting Surrounding Areas
When applying any killing agent, whether chemical or natural, protecting desirable plants and the surrounding environment is important. Herbicides like glyphosate and triclopyr have little soil activity, meaning they are unlikely to be absorbed by the roots of nearby plants if they spill onto the ground. However, you must prevent the chemical from dripping or running off the cut surface, as the herbicide can damage or kill any green foliage it contacts. Using a funnel or a small paintbrush for application provides the greatest control and minimizes the risk of drift.
When using salt-based methods, the potential for soil contamination is a greater concern, especially with sodium chloride. The high concentration of sodium ions can render the soil barren for an extended period, making it challenging to grow anything there afterward. To mitigate this, consider installing a temporary barrier, such as a metal or plastic sheet, buried a few inches into the soil around the stump to contain the substance. Fence off the treated area from pets and children for at least 48 hours following any application.