What is the fastest growing grass in the world?

Bamboo grows faster than any other existing plant. Some of its kinds may spring up for about a meter or more per day and become as tall as ordinary trees. For such impetuous growth, a plant needs a strong root system that will be able to transfer water and nutritious elements to the body. Bamboo roots and stems grow step by step – sometimes roots do better than stems, sometimes, on the contrary, stems suddenly start to grow.

Actually, bamboo is not a tree or a bush. It's a type of grass. Some kinds of bamboo bloom only once in their life and die right after it.