Among Southerners, few plants elicit such strong emotions as bamboo: People seem either to love it or to want desperately to kill it. Though some bamboos grow as tall as trees, all are actually giant grasses. They consist of large, woody stems (culms) divided into sections (internodes) by obvious joints (nodes). Bamboos spread by underground stems (rhizomes) that are jointed and carry buds. The manner in which the rhizomes grow explains the difference between running and clumping bamboos.
In running bamboos, underground stems grow rapidly to varying distances from the parent plant before sending up new vertical shoots. These bamboos eventually form large patches or groves unless spread is curbed. They are generally fairly hardy plants from temperate regions in China and Japan, and they are tolerant of a wide variety of soils.
In clumping bamboos, underground stems grow only a short distance before sending up new stems. These form clumps that slowly expand around the edges. Most are tropical or subtropical.
Mature bamboos grow phenomenally fast during their brief growth periodculms of giant types may increase in length by several feet a day. Don't expect such quick growth the first year after transplanting, though. In larger types, it may take 3 to 5 years to build up a rhizome system capable of supporting culms that grow several feet a day; aboveground growth during a plant's early years will be much less impressive. To get fast growth and great size, water and feed frequently. Once established, plants tolerate considerable drought, but rhizomes will not spread readily into dry soil and not at all into water.
Culms of all bamboos have already attained their maximum diameter when they poke through ground; in mature plants, they usually reach their maximum height within a month. Many do become increasingly leafy in subsequent years, but not taller. Bamboo plants are evergreen, but there is considerable dropping of older leaves; old plantings develop a nearly weed-proof mulch of dead leaves. Individual culms live for several years but eventually die and should be cut out.
See chart for hardiness. Figures indicate temperatures at which aboveground damage occurs; rhizomes may be considerably hardier. The chart gives maximum heights under ideal growing conditions and warmer zones; in colder zones, plants may be considerably shorter and have smaller culm diameters.
Growth habits. The chart classifies each bamboo by habit of growth, which, of course, determines its use in the garden. In Group I are the dwarf or low-growing ground cover types. These running bamboos can be used for erosion control or, in small clumps (carefully confined in a long section of flue tile), in a border or rock garden. Group II includes clumping bamboos with a fountainlike habit of growth. They require no more space than the average strong-growing shrub. Clipped, they make hedges or screens that won't spread much into surrounding soil. Unclipped, they create informal screens or grow singly to show off their graceful form. Bamboos in Group III are running bamboos of moderate size and more or less vertical growth. Curb them and use as screens, hedges, or alone. Group IV includes the giant bamboos. Use running kinds for groves or for oriental effects on a grand scale. Clumping kinds have a tropical look, especially if they are used with broad-leafed tropical plants. All may be thinned and clipped to show off the culms. Thin clumps or groves by cutting out old or dead culms at the base.
Some smaller bamboos bloom on some of their stalks every year and continue to grow. Some bloom partially, at erratic intervals. Some have never been known to bloom. Others bloom heavily, set seed, and die. Some species of Phyllostachys bloom at rare intervals of 30 to 100 years, produce flowers for a long period, and become enfeebled. They may recover slowly or die.
Bamboos are not recommended for year-round indoor culture, but container-grown plants can spend extended periods indoors in cool, bright rooms. You can revive plants by taking them outdoors, but it is important to avoid sudden changes in temperature and light.
Should you find yourself with unwanted bamboo, you can use several methods to get rid of it. Digging it out with mattock and spade is the surest tactic, though sometimes difficult. Rhizomes are generally not deep, but they may be widespread. Remove them all, or regrowth will occur. Starve out roots by cutting off all canes and removing any new shoots that emerge. New shoots are fragile and can be mowed easily. Repeat as neededprobably many times over the course of a year for a well-established grove. Contact herbicide sprays that kill leaves have the same effect as removing culms.