Grow bamboo without fear
Running bamboo, as opposed to well-behaved clumping bamboo, is not something to plant and forget. Maintenance, though not difficult, is absolutely necessary. It’s also not complicated, so don’t be overwhelmed by the vast amount of information out there.
If you can afford it, hiring a landscape contractor who specializes in bamboo is the easiest and best way to go. But if you want to do it yourself, here are the basics:
Planting: Amend with organic material to ensure the rich, well-draining soil needed by bamboo. When designing, be sure to allow enough room around culms for the full-grown stand: Site plants 3-5 feet apart in all directions, depending on size at planting time, then leave at least one more foot between the edge of the bed and fences, neighbors or other beds.
Control spreading: A rhizome trap is considered the most effective method to control spreading. The trap is made by digging a trench (1 foot deep and wide) around the bamboo and filling it with sand. Mulch with 4 inches of wood chips (not bark dust). The sand trench can be used in tandem with a barrier or alone. Barriers are made of 30-inch-tall high-density plastic buried 28 inches deep around the perimeter with 2 inches above the surface. You’ll need at least 1 foot between the barrier and bamboo, keeping in mind how large you want the mature stand. But don’t expect too much of either the barrier or the trench. If not pulled up, rhizomes will eventually jump the barrier or grow past the sand trench.
Maintenance: Removing spreading rhizomes: Two or three times a year, dig around the perimeter of the bamboo inside the sand trench and/or plastic barrier with a Hori-Hori knife or short spade to find unwanted rhizomes. Most often they grow in the top foot of soil and can’t get a grip in the sand, so it’s an easy job to pull them out. For more stubborn rhizomes, use a crowbar to locate and cut back with a Sawzall (reciprocating saw).
Thinning: For health and beauty, thin established stands by removing all weak, dying, dead, leaning or rubbing culms. Cut off at ground level using a reciprocating saw. Because culms are brittle and can easily snap off during the growing season, the best time to prune is August through February. If desired, remove side branches with clippers (limb up) to show more of the culm.
Water: Water regularly, once to twice a week during dry times.
Fertilizer: If you want your bamboo to grow really fast, feed monthly from April through early July with a high-nitrogen fertilizer such as lawn fertilizer.
Running vs. clumping bamboo
The most recognizable bamboo is called running bamboo, with towering culms that can get 75 feet tall, though more commonly 30 to 40, and to 4-7 inches in diameter at maturity. It’s called running bamboo because it sends out rhizomes (underground stems) horizontally and pops up numerous new shoots farther and farther away from the original plant. Without regular maintenance, it will spread rapidly and become unmanageable.
The alternative is called clumping bamboo, a group of plants that have much slimmer culms and are not nearly as tall as running bamboo (also referred to as timber bamboo). They look more like tall ornamental grasses, although with the typical leaves of large bamboo. Clumping bamboo also reproduces by rhizomes. These plants send up shoots close to the base of the clump and spread out very little.