Perhaps you’ve heart of the Titan Arum? This plant only rarely flowers, just like Agave. Agave only flowers at the end of its lifecycle which can last up to fourty years! People flock to botanical gardens when these plants flower. Some bamboo also rarely flowers, which is called “Gregarious Flowering”. This rarely takes place, depending on the species it can last over 100 years before it flowers. Locals aren’t too happy with it though.


Gregarious flowering, a rare phenomenon with plants. It means that plants only flower once every few years, all at once. It depends on the bamboo species how many years that is. It can vary between 30 up to 130 years. When it is time for gregarious flowering, the whole forest will bloom. But not just this specific bamboo forest. All bamboo of that species all over the world will bloom. It is genetically programmed in the plant.


First flowers will grow on the bamboo. Soon the flowers will make room for the fruit, also called bamboo rice. The bamboo does all of this with such dedication that the whole forest will eventually die. All energy will have gone to producing fruits and seeds. When the event of the flowering is completed, the whole forest floor will be covered in fruits and seeds. This makes for an excellent start for a new forest to start growing. The process of flowering can take a few years, depending on the age of the bamboo.


Science still hasn’t figured out why exactly this happens. There have been many theories, but none of them have been confirmed. One theory revolves around the rodents that live in these forests. They think the time is to ensure no rodents can survive on the seeds and they will eventually all pass away before it is time for the next event. Another theory is a lot more probable and says that it is meant for more light and space for the new bamboo to grow.


Living next to a bamboo forest brings lots of economical benefits. The local villages use the bamboo to build basically anything. When the whole forest dies, they lose on essential building materials. It will take a minimum of six years before they can harvest bamboo again.


There are three main consequences ecologically. First of which we shall have a look 8000 years back in time. The domestication of chickens. The modern chicken is a descendent of what we nowadays call “red jungle fowl”, also known as the bamboo fowl. These fowls are wild animals who live on the forest floor. With an event such as gregarious flowering they end up with an abundance of food. As a result they end up laying tons of eggs and producing a lot of offspring. This has led to local societies keeping them as farm animals and eventually the selective breeding which has let to modern day chickens.

 Left the Jungle Fowl, Right the modern Chicken

The flowering also attracts a lot of insects. One of which is known as a ‘stink bug’ or ‘true bug’. There are stories of millions stink bugs coming with the flowering of the bamboo. These bugs will crawly into literally every crevice and hole they can find. They may not bite or harm you, they are hell to have around. Some say they are a tasty treat and see it as a gift from above when they come. They sure are full of nutrition and pets often like to eat them too.


One of the consequences of the biggest impact is the dramatic increase of the rat population. These rats will have a limitless supply of food when the gregarious flowering ends. This gives them the opportunity to multiply their population by tenfold. The rats will eat anything they can find and when they are done with the seeds and fruits they will start with the crops of locals. This leads to complete rice harvests lost to the rats. It is essential to eradicate the population before it’s too late. There is a documentary that investigated this connection called “Rat Attack” by Nova.


Left common rats, Right a (small) bamboo rat

This rat infestation shouldn’t confuse you about the bamboo rats. Although it is called bamboo rat, this animal has nothing to do with the infestations mentioned above. Bamboo rats are more like giant guinea pigs, sizing up to 50cm in length. These bamboo rats live in bamboo forests mostly in China and are seen as a real delicacy by the local population. In many cases it is even more expensive than beef or pork. These rodents aren’t responsible for the nuisance of their smaller namesakes.


There are plenty of bamboo species which will never bloom. Besides, there are also plenty of species which flower sporadically. There are over 1600 species of bamboo and only a handful will gregariously flower. None of the commercial bamboo will flower gregariously. This ensures a steady flow of materials, but it is also good to know ‘our’ bamboo doesn’t contribute to the ecological and economical risks for the local populations. There is no need to worry about the bamboo products you have at home, these are actually really good for the local flora and fauna. You can read more about that in this blog.