Crape myrtles (Lagerstroemia) are admired for their vibrant summer blooms, attractive peeling bark, and colorful fall foliage. Understanding their root system is helpful for successful planting and long-term health, aiding in proper placement and ongoing care.
Understanding Crape Myrtle Root Systems
Crape myrtles generally possess a fibrous, shallow, and non-invasive root system. Unlike some larger tree species, they do not typically develop a deep taproot. Instead, their roots spread horizontally, forming a network closer to the soil surface.
The non-aggressive nature of crape myrtle roots means they are unlikely to cause significant damage to foundations, pipes, or other underground utilities. They are often planted near sidewalks and driveways because their roots typically do not threaten these structures. Minor issues can occur if planted too close, though severe damage is rare.
Root Depth and Lateral Spread
While crape myrtle roots are primarily shallow, their lateral spread can be extensive. Most feeder roots, responsible for water and nutrient uptake, reside within the top 12 to 18 inches of soil.
The horizontal reach of a crape myrtle’s root system can extend significantly, often to a diameter roughly equal to the tree’s canopy spread or even wider. Some sources indicate roots can spread one and a half to two times the canopy’s diameter. This wide, shallow spread helps the tree absorb surface moisture and nutrients efficiently.
Managing Roots Near Structures
When planting crape myrtles, consider their mature size and root spread, especially near structures. While their roots are not considered invasive, planting too close to foundations, driveways, or sidewalks can lead to minor issues over many years. For standard-sized crape myrtles, a planting distance of at least 6 to 10 feet from structures is recommended to allow for full growth and air circulation.
Smaller or dwarf varieties may be planted closer, with recommendations suggesting 3 to 4 feet. Although roots are not strong enough to crack foundations, they could cause slight lifting or minor cracking of shallow concrete over extended periods.
Root Care for Optimal Health
Promoting a healthy crape myrtle root system begins with proper watering, particularly during establishment. Newly planted crape myrtles need consistent, deep watering to encourage robust root development. Watering deeply once or twice a week during the first growing season is often sufficient.
Established crape myrtles become more drought-tolerant, but they still benefit from deep, infrequent watering during dry periods. Applying a layer of mulch around the base helps retain soil moisture, regulate soil temperature, and suppresses weeds that might compete for resources. Avoiding disturbance to the root zone, especially during construction or landscaping, further supports a strong and healthy root system.