How Does Bamboo Grow?

The fastest-growing plant in the world, bamboo is a little unusual in that its culms do all their growing in a single season. It does not produce secondary growth, although it will grow new leaves each year. In addition, it has an unusual growth pattern. It will grow fastest in its preferred conditions in USDA Zones 5 and above.

About the Bamboo Family

Bamboo is a grass. Clumping bamboos are like fescue, in that they spread slowly from a single root mass. Running bamboos are like Bermuda grass, spreading through horizontal stolons from which stems spring up. Like many grasses, bamboo has a strong growing period in spring and early summer, then puts its energy into growing roots. It is semi-dormant in winter.

Fastest Growing Bamboos

A few bamboos can literally grow overnight. Among these:

  • Phyllostachys moso is a timber bamboo that can grow 10 feet in three weeks.
  • Phyllostachys vivax, greenstripe bamboo, is hardy in colder climates.
  • Phyllostachys aurea, golden bamboo; considered invasive and illegal in some states.
  • Bambusa dolichomerithalla, silvestripe bamboo; culms are only one inch in diameter.

Bamboo Colonies

A single bamboo plant is actually the nucleus of a bamboo colony. About 80 percent of this colony – which will become a bamboo grove – is underground. The root mass builds until the plant is mature, at which point the initial plant and some of the early culms die off. Early culms may look very different from the mature plant, but a bamboo grove is really a single organism with identical culms.

Early Bamboo Growth

When you first plant a bamboo, it must establish itself before it can put much energy into growing into a large clump. It focuses most of its growth efforts into the root mass during this early period. Although it will send up some culms, they will not be large or numerous. Culms will still only grow for about 60 days. Bamboos reach maturity in four to 15 years.

Bamboo Expands its Cells

When a bamboo culm first emerges from the ground, it has all the cells it will have as an adult stem. In other plants, growth occurs because the plant creates new cells, like building a wall with individual bricks. Bamboo grows by filling each of its cells with water, stretching them lengthwise. This is the secret of its extremely fast growth.

How Culms Grow

A culm emerges from the ground during the spring growth period and grows for about 60 days. At that point it stops growing and will not increase in height or diameter. It also produces leaves and branches during the growth period. The lifespan of a culm is around 10 years in most varieties.