Flowering of bamboo is a peculiar phenomenon because it occurs rarely and all the bamboos of a same species bloom massively bloom at once and then die.
Most bamboo species flower only every 40 to 130 years, all plants bloom at the same time, no matter how old the culms, and then they all die.
The last massive blooms of Melocanna baccifera covered an area of 26,000 km² in Mizoram (India) in 2004. This species blooms every 50 years, so once a generation.
In 1994 and 1995 Bambusa chunii and Bambusa flexuosa flowered in Hong Kong.
And in 2006 oxytenanthera abyssinica floweredmassively in Mali.
Bamboo flowering is followed by famine, death and destruction:
This is a Chinese proverb but bamboo flowering is also considered a bad omen in other countries and continents.
The reason for this is that after flowering, bamboo produces seed. A huge food supply is then available for rats and the rat population grows explosively.
After all the bamboo seeds are eaten, the rats turn to other food sources and destroy crops planted by man. The harvest is then destroyed which results in famine.
And since rats are responsible for propagation of the plague, a plague epidemic erupts after bamboo flowering in the affected areas.
There is also an important economic impact: bamboo is used for many things, such as timber, and it will take years before the new plants are big enough to be usable.
So bamboo flowering has a severe impact that might disrupt the social structure. It is therefore not surprising that they say in Mali that bamboo flowering is a bad omen for kings, conquerors and chiefs.
Types of flowering:
Bamboo flowerings are different according to species:
1. Synchronous flowering:
Most bamboo species exhibit synchronous flowering. This is when all plants of the same species of bamboo flower at the same time, all around the world.
One reason for this is that bamboo is often clonally propagated by removing suckers. A plant in Asia might have genetically identical descendants on other continents.
But why exactly they flower at the same time all over the world, is still a mystery. It is assumed that the plant is genetically programmed to reach a certain age and then to bloom.
The bloom also occur independently of the age of the culms: both young and old culms flower at the same time.
After flowering, fruiting takes places which depletes the plant and the plant dies.
This bloom takes place every 40-130 year, depending on the species.
2. Sporadic flowering:
Sporadic flowering occurs at regular intervals, for example every 10 years. The length of the interval is dependent on the species.
After sporadic flowering plants usually do not die, but this also depends on the species.
And unlike synchronous flowering, sporadic flowering does not occur massively all over the world but rather regionally.
3. Annual flowering:
A small number of bamboo species blooms annually, like most grasses.
The plants usually do not die after annual flowering.