The crepe myrtle (Lagerstroemia indica) is a popular landscape tree, but its removal is challenging due to its aggressive growth habit. Even after the main trunk is cut down, the extensive root system contains stored energy that fuels the rapid growth of new shoots, known as suckers. These suckers can emerge far from the original trunk for several seasons, making complete root eradication a persistent process. Eliminating the root system requires a targeted, multi-step approach focusing on chemical application and physical removal.
Preparation Steps Before Root Removal
The first step in root eradication is reducing the amount of plant material that needs treatment. Cut the main trunk or trunks as close to the ground as possible, leaving a stump no more than six inches high. Clear the surrounding soil to expose the root flare, where the trunk meets the large structural roots.
If chemical treatment is chosen, prepare the remaining stump to maximize herbicide absorption. Use a large drill bit to bore multiple deep holes into the top surface of the stump, especially around the outer ring. This outer ring, directly beneath the bark, contains the living cambium layer that actively transports nutrients and applied herbicide down into the root system. The holes serve as reservoirs to ensure the chemical penetrates the vascular tissue.
Targeted Root Killing Methods
Two effective strategies exist for eliminating the remaining root system: a systemic chemical approach or thorough mechanical removal. The choice depends on the stump’s size, proximity to desirable plants, and the urgency of removal. Both methods are effective when executed precisely.
Chemical Application
Systemic herbicides like glyphosate or triclopyr are effective for killing woody plants by translocating the chemical throughout the root structure. These chemicals must be applied to the freshly cut surface of the stump, specifically to the outer ring where the cambium is active. Application should occur immediately after the tree is cut because the cambium layer begins to seal itself within a few hours, reducing herbicide uptake.
Alternatively, concentrated herbicide can be poured directly into the pre-drilled holes, allowing it to wick down into the roots. Triclopyr-based herbicides are often considered more effective for killing woody plants than glyphosate. Always wear appropriate personal protective equipment (PPE), such as gloves and eye protection. Apply the chemical carefully to prevent runoff into the surrounding soil or contact with nearby vegetation.
Mechanical Removal
The most immediate and comprehensive method for eliminating the stump and its primary root crown is using a stump grinder. This machine physically pulverizes the remaining wood and the top portion of the root system. To prevent the regeneration of suckers, the grinding process must extend sufficiently below the soil line.
A depth of at least six to twelve inches below grade is required to remove the bulk of the root crown and the concentration of stored energy. For smaller crepe myrtles, manual removal is an option, involving digging around the root ball to sever and extract the roots. This is a labor-intensive process, and success relies on removing all significant root sections that could sprout new growth.
Monitoring and Confirmation of Root Death
Root death is a gradual process, particularly with persistent species like the crepe myrtle, and requires consistent monitoring. Successful eradication is confirmed only when no new suckers appear over a full growing season, typically nine to twelve months. This waiting period allows the systemic herbicide time to circulate or confirms that mechanical removal eliminated the regenerative capacity of the roots.
If new shoots or suckers emerge, they indicate that living root sections remain and possess stored energy reserves. These new growths should be spot-treated immediately with a systemic herbicide or manually pulled out. Applying herbicide directly to the foliage allows the chemical to be absorbed and transported down to the root fragment. Disposal of any chemical-treated wood chips or extracted root material should follow local regulations.