When Bamboo Flowers

The flowering of bamboo is one of the rarest and most unusual events among plant life.

A few years ago, Dr. Thomas Soderstrom planted several specimens of bamboo from Puerto Rico at the Smithsonian Institution in Washington, D.C. When the leaves of the only surviving plant started to fall off and the plant looked sickly, Dr. Soderstrom was sorely disappointed. “But then I realized this was what happened when bamboos were about to flower, a rare event,” said Dr. Soderstrom. “Then I got excited.” A friend in Puerto Rico told him that the species was in bloom “all over the island.” That particular species had last flowered in 1910, 66 years earlier.

In 1979 another beautiful and popular species, the umbrella bamboo, started to flower, first in northern Europe, then in North America and eventually all over the world. That was the first time the plant was seen to bloom since its discovery in the Himalayas in the 1800’s. But that was also the umbrella bamboo’s last show.

Most species of bamboo have a built-in timing mechanism in the cells that tells them when to flower—and when to die. It may be triggered at intervals ranging from 10 to 120 years, depending on the species. When that time comes, young and old plants of that species around the world follow the signal and begin to perform their final ritual. First, a particular plant flowers, then the whole grove, then all the bamboos of that species in the area and finally all around the world. Within a year or two, the whole species dies out. Does this mean the end of the plant? Happily, no. Regeneration will take place by means of the numerous rice-kernellike seeds resulting from the flowering, but this may take a decade or longer.

When bamboo blooms, branches near the top of the main stem burst out with tiny, white blossoms. In many species the flowers are covered by green scales, or bracts, making them quite difficult to see. This adds to the bamboo flower’s being a seldom-seen rarity. In fact, botanists find them hard to examine with the unaided eye—they must be brought into the laboratory and studied under a microscope. And studied they are, because bamboo is so extensively used in the Far East, India and South America that when a growth suddenly dies out, the effect can be devastating. The disappearance of the umbrella bamboo, for example, almost wiped out the principal food supply of the giant pandas in Szechwan Province, China—a near disaster.