Bamboo blossom is a natural phenomenon in which the bamboos in a location blossom and become hung with bamboo seeds. This is commonly found in China, Myanmar and India.
Bamboos usually have a lifecycle around 40 to 80 years, varying among species. Normally, new bamboos grow up from bamboo shoots at the roots. At infrequent intervals for most species, they will start to blossom. After blossom, flowers produce fruit (called "bamboo rice" in parts of India and China). Following this, the bamboo forest dies out. Since a bamboo forest usually grows from a single bamboo, the death of bamboos occurs in a large area.
Many bamboo species flower at extremely long intervals such as 65 or even 120 years. These taxa exhibit mass flowering (or gregarious flowering), with all plants in a particular cohort flowering over a several-year period. Any plant derived through clonal propagation from this cohort will also flower regardless of whether it has been planted in a different location. The longest mass flowering interval known is 130 years, for the species Phyllostachys bambusoides (Sieb. & Zucc.). In this species, all plants of the same stock flower at the same time, regardless of differences in geographic locations or climatic conditions, and then die. The lack of environmental impact on the time of flowering indicates the presence of some sort of "alarm clock" in each cell of the plant which signals the cessation of vegetative growth and the diversion of all energy to flower production. This mechanism, as well as the evolutionary cause behind it, is still largely a mystery.
One hypothesis to explain the evolution of this semelparous mass flowering phenomenon is the predator satiation hypothesis, which argues that by fruiting at the same time, a population increases the survival rate of their seeds by flooding the area with fruit. Therefore, even if predators eat their fill, seeds will still be left over. By having a flowering cycle longer than the lifespan of the rodent predators, bamboos can regulate animal populations by causing starvation during the period between flowering events. Thus, the death of the adult clone is due to resource exhaustion, as it would be more effective for parent plants to devote all resources to creating a large seed crop than to hold back energy for their own regeneration.