Runners and Clumpers
American Bamboo Society Logo
Promoting the Beauty and Utility of Bamboo

Running and Clumping Bamboos

“It might be expected that a plant reaching a height of 100 feet.…would resemble a typical tree with a single trunk and root structure, but it does not. Instead, bamboo’s underground system of rhizome roots is no diffeent from turfgrass, and the rhizomes’ characteristics are a primary factor in identifying bamboo genera.” Nancy Moore Bess

Bamboos are divided into two main types:

Clumping bamboos

Clumping (sympodial) types have a very short root structure, are genetically incapable of expanding more than few inches a year and will generally form discrete clumps. The clumps slowly enlarge as new culms emerge every year, and may require anywhere from 2-10 feet or more of space in order to reach their mature height, depending on species. Clumpers make excellent specimen plants and will form very dense screens, but more slowly than runners. Except for the Fargesias, the clumpers tend to be less cold-hardy than runners.

Clumping grove appearance Clumping root structure

Running bamboos

Running (monopodial) types spread variously, sending out underground runners, or rhizomes, which sometimes emerge far from the parent plant. Runners fill in the spaces between plantings faster, making them ideal for screens, hedges, and the popular open grove look. Runners may be easily contained, as described below, since the rhizomes grow sideways at a depth of about 2-18 inches. Most are also very cold-hardy.

Running grove appearance Running root structure

Containment of Bamboos

Runners: The safest containment methods for runners are 1) planting in containers, or 2) installing a vertical 30-40 mil thick plastic rhizome barrier a 22-30 inches deep around the perimeter of the area in which the bamboo is to be contained. The advantage of this material is that even large plantings of bamboo can be surrounded with a single length of plastic, requiring only one seam. It is prefereable to cement (which often develops cracks), or metal (which rusts and requires many seams), is less expensive, and lasts 20-30 years if installed properly. It comes on a 300 ft. roll, can be cut to any length and installed in any shape desired. (NOTE: When planting on very steep slopes or planting very large giant timber varieties in soft, sandy soil, it may be necessary to use a 36 inch deep barrier. Please refer to the ABS or Bamboo Sourcery Web site for detailed installation instructions).

A less defined way to contain a runner (in climates that have several dry months) is to water only the area in which the plants are wanted and nowhere else within 10 to 20 feet. Dry soils block expansion. Spreading rhizomes require moisture and grow primarily during the warm summer months when most of the western states are dry. Cutting off new shoots coming up wherever they’re not wanted complements and completes this method.

A water-filled stream or ditch can also effectively block the spread of bamboo, since rhizomes and roots cannot tolerate extended periods of saturation. Water need only be present for one season a year.

Clumpers: With clumpers, it is not necessary or effective to surround the plant with a plastic root barrier. If necessary, clumpers may be shaped and prevented from putting pressure on any surrounding structures by removing new shoots at soil level when they begin to encroach more closely on those structures.

One must keep in mind, however, that the root ball of a clump must be allowed to reach a certain size in order to develop culms of a mature height. The space required will vary depending on size of species. Height of culms may be limited if too small a space is allowed for the roots.

Acknowledgements ~ Many thanks to Nancy Moore Bess for the use of the root structure diagrams from her new book, Bamboo in Japan (published by Kodansha America, Inc.)

Bamboo Sourcery
666 Wagnon Road,
Sebastopol, CA 95472
Ph: (707) 823-5866
Fax: (707) 829-8106

Send us a message - | - This page was last modified on Sunday, 2008-10-26 18:33