Bamboo is a popular ornamental grass valued for its rapid growth, providing quick privacy screening and a unique aesthetic. However, this aggressive characteristic often leads to disputes and frustration. Because the plant’s classification is often misunderstood, proper management is difficult. This guide clarifies the definition of bamboo and provides strategies for its containment and removal.
The Distinction Between Aggressive and Invasive
The term “invasive species” carries a specific legal and ecological meaning that most bamboo varieties do not meet. To be classified as invasive, a species must be non-native and cause environmental or economic harm, such as displacing native plants in natural habitats. Most cultivated bamboo is non-native but rarely escapes cultivation to cause widespread ecological disaster.
Instead, bamboo is best described as an aggressive plant because it spreads quickly and vigorously within a garden or cultivated area. The issue is typically one of property management, where the fast-spreading root system breaches physical boundaries and moves into lawns or a neighbor’s yard. Understanding this distinction helps focus control efforts on physical containment rather than ecological concerns.
Understanding Running and Clumping Rhizomes
The speed and distance of bamboo’s spread are dictated entirely by its underground stem structure, known as a rhizome. Bamboo species are categorized into two main groups based on rhizome morphology.
Running bamboo (monopodial) possesses long, thin rhizomes that extend horizontally away from the main plant. These rhizomes can travel great distances, sometimes up to 20 feet in a single growing season, before sending up new shoots.
Clumping bamboo (sympodial) has short, thick, U-shaped rhizomes that curve upward immediately to produce new culms close to the parent plant. This results in a dense, compact growth habit that expands slowly, often only a few inches each year, making it much easier to manage. Popular examples of running types include many Phyllostachys species, while most Fargesia and Bambusa species are clumpers. The choice between the two is the most important decision for long-term control.
Proactive Containment Strategies
Selecting a clumping variety is the most effective initial step in proactive containment, as these types are genetically predisposed to stay put. If a running variety is desired, a physical root barrier is necessary to prevent aggressive spread. These barriers are typically made from durable, non-puncturable high-density polyethylene (HDPE).
A thickness of at least 60 to 80 mil is recommended to resist the force of the growing rhizomes. The barrier must be installed vertically in a trench 24 to 30 inches deep. To ensure rhizomes do not “jump” the barrier, the material should extend about two inches above the soil line, forcing upward-growing rhizomes to become visible for easy pruning. Regular maintenance involves monitoring the above-ground lip and periodically pruning the soil just outside the barrier to sever any escape attempts.
Methods for Removal and Eradication
Removing an established, uncontained stand of running bamboo requires a persistent, multi-year approach.
Physical Removal
Intensive physical removal involves cutting down the culms and digging out the entire rhizome mass. Care must be taken to remove every piece of the thick, underground stems. The soil must be monitored, as even small fragments of rhizome can sprout new growth. For large stands, a mattock or heavy equipment is often necessary to break up the dense root mat.
Starvation by Cutting
A less labor-intensive method is the continuous starvation of the plant by frequent cutting or mowing. Since bamboo is a grass, regular mowing of new shoots every one to two weeks will eventually deplete the energy stored in the underground rhizomes. This method requires two to three years of consistent effort to be fully effective.
Chemical Treatment
Chemical treatment uses a systemic herbicide containing glyphosate. There are two primary application methods:
- The most effective method involves cutting the culms back and allowing the new foliage to fully expand, typically in mid-to-late summer, before spraying the leaves with the herbicide.
- Alternatively, a concentrated glyphosate solution can be applied directly into the freshly cut, hollow stubs of the canes, allowing the chemical to be quickly absorbed and translocated to the rhizomes.
Successful eradication requires consistent effort, as the plant’s extensive underground network makes it highly resilient.