The flowering of bamboos, like their vegetative growth, is liable to be on a grand scale. Large quantities of pollen may be formed, which sometimes induce a kind of hay fever. The scale of the seed production can be gauged from the statement that, from one clump of Dendrocalamus strictus Nees, the crown of which covered an area of about 40 square yards, grain was collected to the amount of 160 seers (330 lb.), besides a quantity naturally shed, which resulted in a dense mass of seedlings around the clump. Another record describes the wild tribes of the Assa forest gathering the seed of the same species in March 1901; the outer culms of each clump were cut, one by one, at a height of about 4 ft., and each was laid on the ground which had previously been cleared and swept. The culm was beaten with stout sticks until all its caryopses had fallen; they were then carefully winnowed by children. One adult could collect 2–3 seers (4–6 lb.) of seed in a day.

The periodicity of flowering in the bamboos seems to vary within wider limits than in any other homogeneous group of plants. In South America, annually flowering species are common; they belong to Arundinaria, Bambusa, Guadua, and other genera. In India, on the other hand, only a limited number of species flower every year, e.g. Arundinaria Wightiana</i. Nees, Bambusa lineata Mun. and Ochlandra stridula Thwaites. Many of the Asiatic bamboos have a more prolonged life-cycle, and show themselves, in Riviére's phrase, “assez avares de leurs fleurs”.