Crepe myrtles (Lagerstroemia indica) are popular for their summer blooms, but removing them presents a unique challenge due to their aggressive root systems and tendency to produce new sprouts. Once the trunk is cut, the remaining stump and roots store significant energy, prompting the plant to aggressively send up new shoots, known as suckers, as a survival mechanism. Successfully eliminating the plant requires deliberate mechanical or chemical action to destroy the root crown and exhaust the energy reserves in the roots.
Preparation Before Treatment
The initial step for any removal strategy is to cut the main trunk as close to the ground as possible, creating a “low cut.” This maximizes the surface area of the stump for grinding or chemical application. Clear the area around the base, removing any mulch, dirt, or debris that might interfere with the subsequent treatment.
If chemical application is planned, the cut surface must be fresh to ensure maximum absorption of the herbicide. If the stump has been cut for more than a few hours, the outer bark layer will begin to dry and seal, blocking chemical uptake. Scraping or peeling back the outer bark of an older stump exposes the light-colored, moist phloem layer, which transports the herbicide down to the root system. Always wear appropriate protective gear, such as gloves and eye protection, especially when handling chemicals.
Physical Removal Techniques
The most thorough and immediate method for removing the stump and preventing regrowth is physical elimination, typically achieved through stump grinding. A commercial stump grinder uses a rotating cutting wheel to chip away at the wood, effectively destroying the stump. For a crepe myrtle, the grinding depth should extend at least 6 to 12 inches below the surrounding soil line to eliminate the main root crown and the upper, active portions of the root flares.
Grinding the stump into wood chips prevents the immediate re-sprouting that occurs when a stump is left intact. However, some lateral roots may remain alive beneath the soil, which can still produce suckers. For homeowners without specialized machinery, manual removal involves extensive digging around the stump to expose the roots. The large roots must be severed with an axe or reciprocating saw before the entire root ball can be pried out.
Chemical Eradication Methods
Chemical treatment is an effective option for killing the entire root system without the labor of physical removal, relying on systemic herbicides to translocate through the plant’s vascular tissue. The most reliable application technique is the “drill and fill” method, which creates reservoirs for the chemical directly into the stump.
Holes should be drilled downward at a slight angle, such as 45 degrees, into the freshly cut surface, concentrating the holes just inside the bark ring where the phloem is located. The concentrated herbicide must be applied immediately after drilling, ideally within minutes, before the wood begins to dry and seal the transport vessels.
The most effective herbicides for woody plants contain active ingredients like glyphosate or triclopyr. Glyphosate products with an active ingredient concentration of 20 percent or more are recommended for cut stump treatment. Triclopyr amine products containing at least 8 percent active ingredient are also suitable.
Triclopyr is often favored in areas near turfgrass because it is less likely to harm grasses compared to other broadleaf herbicides. Always refer to the specific product label for safety precautions, application rates, and environmental considerations. The stump will gradually die and begin to rot, a process that can take several months to over a year.
Managing Regrowth and Suckers
Crepe myrtle roots possess significant stored energy, which often results in the emergence of persistent suckers from the roots even after the main stump has been treated. These sprouts are the plant’s attempt to survive by creating new foliage to photosynthesize and replenish the depleted root energy.
The most straightforward strategy for managing suckers is immediate and consistent physical removal, cutting them off as soon as they appear to prevent them from photosynthesizing. Repeated cutting starves the root system by continually forcing it to use its reserves without the ability to “recharge” through new growth.
If suckers are numerous or particularly stubborn, a systemic herbicide can be applied directly to their freshly cut stems or foliage. Allowing the suckers to grow a few leaves before treating them can increase the absorption surface area for the chemical, ensuring better translocation to the roots. Methods like pouring salt directly into the stump or smothering it with plastic are generally ineffective or too slow for a resilient species like the crepe myrtle.