Bamboo is a highly versatile plant, technically classified as a perennial evergreen grass belonging to the family Poaceae. Growing this plant directly in the ground, rather than in a container, allows it to reach its full size potential. Bamboo species are broadly divided into two major types: running types, which spread aggressively, and clumping types, which expand slowly in a tight radius. Proper care focuses on optimizing the plant’s environment while managing its vigorous underground growth.
Selecting the Site and Soil Preparation
The initial selection of the planting site is a primary factor in the long-term health of the bamboo. Most species flourish best in a location that receives full sun to partial shade, though some varieties, like those in the Sasa genus, prefer the filtered light of an understory. Adequate space must be considered upfront, especially for running types, which spread laterally and can quickly become a containment issue.
Bamboo requires well-draining, porous soil that retains moisture without becoming waterlogged. Ideal soil conditions involve a slightly acidic to neutral pH range, with optimum growth occurring between pH 5.5 and 6.5. Incorporating substantial organic material, such as well-rotted compost or manure, into the planting area significantly improves both drainage and fertility. This ensures the rhizomes have a loose medium for healthy development.
Watering Requirements for Established Bamboo
Once the bamboo is established in the soil, its watering regimen should prioritize depth over frequency. Deep, infrequent watering encourages the root system to grow downward, resulting in a more resilient plant. Instead of daily, shallow sprinkles, the goal is to thoroughly soak the soil to a depth of at least eight to twelve inches.
Watering is necessary when the top few inches of soil begin to dry out, often translating to a deep watering once or twice a week, depending on local climate. An established plant under water stress will exhibit rolling its leaves lengthwise to conserve moisture. During hot, dry summer months, frequency must be increased, and the watering schedule should be reduced during the cooler, dormant winter season. Applying an organic mulch layer helps maintain consistent soil moisture by reducing evaporation.
Feeding Schedules and Nutrient Needs
Bamboo is a heavy feeder that benefits from a consistent nutrient schedule due to its rapid growth rate. The preferred fertilizer should be high in nitrogen, with a high first number in the NPK ratio, such as 20-5-10. This nitrogen content supports the development of new culms and dense foliage.
Fertilization is best applied in the early spring, just before the new shoots emerge, and again in mid-summer to support leaf and rhizome development. Allowing the plant’s own leaf litter to decompose around the base is helpful. Bamboo leaves contain a high concentration of silica, which is recycled back into the soil by the decomposing mulch. This silica strengthens the culm walls, making the canes more structurally sound and resistant to pests.
Control and Maintenance of Spreading Growth
Managing the underground rhizome structure is the most time-intensive aspect of growing bamboo in the ground. For running bamboo, which spreads via long, lateral rhizomes (leptomorph), containment is best achieved by installing a physical barrier. This barrier should be made of a non-degradable material, such as High-Density Polyethylene (HDPE) plastic.
The barrier must be installed to a depth of 28 to 30 inches, as the rhizomes typically travel in the top 18 inches of soil. To prevent the rhizomes from growing over the top, the barrier should protrude two inches above the soil line and be angled slightly outward. Alternatively, for running types, a sharp spade can be used annually to sever any outward-growing rhizomes, a process called root pruning.
Clumping bamboo, which has short, thick rhizomes (pachymorph) that expand slowly, rarely requires a barrier. Maintenance for clumping types involves an annual thinning of the older, weaker culms to create air circulation and promote the growth of newer, larger canes. This is done by cutting the oldest culms at ground level, which also limits the overall diameter of the clump.