The primary reason bamboo is known for "taking over" lies in its unique growth structure. Bamboo spreads via underground stems called rhizomes. There are two main types of rhizome systems, which fundamentally dictate the plant's behavior. "Running" bamboo (monopodial) features leptomorph rhizomes that grow horizontally, often several feet from the parent plant, before sending up new shoots. This allows it to colonize large areas rapidly. In contrast, "clumping" bamboo (sympodial) has pachymorph rhizomes that grow in a tight, u-shaped curve, producing new shoots very close to the main plant. This results in a dense, slowly expanding cluster that is far more manageable in a yard.
From a plant's perspective, the single most important decision you make is selecting the right type. If your goal is to plant bamboo without it taking over, you must choose a clumping variety. Clumping bamboos, such as those from the genera Fargesia or Bambusa, have a self-contained growth habit. Their rhizomes are incapable of the long-distance travel that characterizes running types. They will expand their circumference gradually, typically only a few inches per year, forming a well-behaved ornamental grass clump. Running bamboos, like those from the genus Phyllostachys, are inherently invasive by design and should be avoided unless you are prepared for extreme containment measures.
If you are determined to plant a running bamboo, or even to provide an extra barrier for a large clumping type, physical containment is non-negotiable. The most effective method is installing a high-density polyethylene rhizome barrier. This specialized plastic is installed in a trench around the bamboo planting area, forming an impenetrable wall that the rhizomes cannot breach. The barrier must be installed at a depth of at least 24-30 inches, with a few inches above the soil surface to catch any rhizomes that try to jump over. Without this robust barrier, the rhizomes of a running bamboo will exploit any weakness, including small gaps or shallow installations, and continue their spread.
Bamboo is a vigorous plant, and even clumping types require some monitoring. The most effective maintenance practice is annual root pruning. Using a sharp spade, you can cut around the perimeter of the bamboo's clump, severing any outward-growing rhizomes. This is best done in the fall. For running bamboo contained by a barrier, this practice is essential to check for and cut any rhizomes that may have reached the top of the barrier. Furthermore, promptly removing any new shoots (culms) that appear outside your designated area is crucial. These young shoots are tender and easy to cut or mow over, preventing them from maturing into full-sized canes.
