Bamboo Flowering: Learn All About Bamboo Flowering Habits

Bamboo flowering is the pattern of flowering of bamboo plants. Bamboo (subfamily Bambusoideae) is a perennial evergreen plant that grows all over the world. Some bamboo species flower sporadically or annually, and a few bamboo species experience gregarious flowering or mass flowering. Gregarious flowering is an unusual flowering phenomenon that occurs only once over a span of decades, simultaneously with other plants of the same population, in widely dispersed geographic locations.

When flowering occurs, the bamboo plants produce masses of seeds, usually from the ends of branches. The branches extend outward from the bamboo stems, or culms, of mature bamboo plants. The bamboo seeds fall to the ground, and upon germination, new bamboo grows from the seeds.

There are three categories of flowering habits for bamboo. Every species falls into one category, depending on when bamboo flowers:

1. 1. Annual flowering: The least common type of bamboo flowering is annual flowering. Bamboo species that that belong to the genus Schizostachyum flower annually.
2. 2. Sporadic flowering: Certain species of bamboo plants have irregular flowering intervals known as sporadic flowering. In addition to environmental factors, intensely managed and cultivated types of bamboo are more likely to flower sporadically. When bamboo sporadically flowers, it generally happens individually, and the bamboo does not die after the flowering is complete.
3. 3. Gregarious flowering: The most remarkable kind of bamboo flowering is known as gregarious flowering. This occurs when a large population of the same bamboo species flower simultaneously after being in the vegetative phase for decades—sometimes as long as one hundred and thirty years. After flowering, fruiting, and producing seed, their life cycle is complete, and the entire bamboo forest dies off.

Consider the following notable species of bamboo and their flowering patterns:

1. 1. Berry bambo (Melocanna baccifera): Berry bamboo is a hybrid species that shows sporadic flowering as well as periodic massive gregarious flowering.
2. 2. Black bamboo (Phyllostachys nigra): Black bamboo undergoes gregarious flowering every few decades. The last worldwide flowering of black bamboo began in 2008.
3. 3. Common bamboo (Bambusa vulgaris): This species of common clumping bamboo flowers sporadically. It is not known to ever set seed, even when flowering.
4. 4. Chilean bamboo (Chusquea culeou): This species—along with some species of the genera Fargesia, Guadua, and Pleioblastus—can experience sporadic and gregarious flowering.
5. 5. Hedge bamboo (Phyllostachys glauca): This species of bamboo plants flower on a gregarious flowering cycle.
6. 6. Japanese giant timber bamboo (Phyllostachys bambusoides): This bamboo species has one of the longest known flowering cycles, at one hundred and thirty years.
7. 7. Taiwan giant bamboo (Dendrocalamus latiflorus): This is a fairly common type of sporadically flowering bamboo.
8. 8. Tortoise-shell bamboo (Phyllostachys edulis): This type of bamboo has spread to Africa for commercial growing, and has shown gregarious flowering in the wild.

In gregarious bamboo flowering, members of a single population of bamboo, even those removed from their home environment, flower simultaneously, produce seed, and then die. The causes remain mysterious, but many botanists believe gregarious flowering is a genetic factor.

Many widely-distributed plants start as cuttings from the same mother plant or parent plant. Botanists believe descendants from the mother plant share a genetic trait with a biological alarm clock that signals the plants to flower after a certain period of growth.

The effects of bamboo flowering sporadically or annually are largely similar to those of other plants. However, when there are massive synchronized flowering events over large areas, there can be significant disruptions in the local ecology, including:

• Increase in rodent population: With such a massive increase in seeds as a food source, gregarious blooms can spur a massive rodent population boom. This can have devastating consequences for local human communities. For example, Melocanna bambusoides bamboo flowers every thirty to thirty-five years along the Bay of Bengal in India, and the increase in the rat population decimates crops and spreads disease.
• Loss of building material: The dying off of a bamboo forest after flowering can lead to widespread disruption. In addition to using bamboo shoots for culinary use, communities also rely on timber bamboo and other types of woody bamboo for construction and other industrial applications.
  
• Ecosystem: Mass bamboo blossoms can affect animals reliant on bamboo plants as a food source. The endangered giant panda, which subsists on bamboo shoots and leaves, has been affected by mass die-offs following flowerings.
• Lighting strikes: After the mass die-off of recently-flowering plants, the large biomass available is susceptible to ignition from lightning strikes, which can cause fires. Fires can clear the land of other competitor species and allow the next generation of bamboo plants to gain an advantage.
• Renewal: Gregarious blooming can affect human communities that rely on bamboo, but it is a part of these species' life cycle. The abundance of seeds eventually germinate, leading to a renewal of the local bamboo forest and vegetative growth. This has been seen in China, India, and Japan, where massive flowerings have been recorded going back thousands of years.

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