how long does it take for a bonsai to grow?

A true Bonsai? About 6-8 years before you can really start to prune it.

A bonsai is not a type of plant. It is the art of growing ornamentally dwarfed trees.Bonsai can be any of hundreds of types of trees and plants. It would depend on the particular one you are trying to grow. Also it would depend on the care you gave the tree. Are conditions optimal? Are you properly fertilizing? Is the soil ph correct? Etc..What are you looking to grow?I disagree that it takes 6-8 years to grow a bonsai tree. Depending on what type it can be less than a year before it is a nice size. There are very small bonsai trees. It is an art so it depends on the look you are going for as well.