The Phenomenon

In bamboos that flower at long intervals, the flowering is typically of two types - a) gregarious and b) sporadic.
In gregarious flowering, entire populations in a given area will bloom, with all clumps, and all culms of the clumps flowering within a period of time that may extend from a few months to a few years. 

In sporadic flowering, not all culms in a clump will flower, or scattered subsets of clumps of the population will flower. While some species flower gregariously, and others flower sporadically, there are also species that flower both gregariously and sporadically.

Flowering, even when it occurs, need not necessarily result in fruit bearing/ seed setting.

The periodicity of flowering in bamboo species varies.

-Some species flower annually, or at short intervals.
-Most commercially significant species that exhibit gregarious flowering characteristics flower at long, often regular intervals.
-Some species that exhibit sporadic flowering do so at irregular intervals.

The impact of flowering varies.

• There are some species that die after the first and only fruiting.
• There are some species that die in part, after fruiting, and renew the dead parts.
• There are some species that do not die but flower and bear fruit at regular/irregular intervals

In gregarious flowering, the affected clumps and therefore all their culms will invariably die.
In sporadic flowering, when some culms flower, the affected culms will die, but the clump may or may not die, and, in fact may even be rejuvenated and reinvigorated to continue to throw up healthy culms.
In sporadic flowering, when an entire clump flowers, in most cases the clump will die, but there are species in which the clump will not dire, but continue to produce healthy culms.