A tree that could be used for bonsai is not small in nature. If left to grow in the open soil, a bonsai tree would grow as big as any other tree. But in a pot, the tree will not grow very big. To help keep it small, the owner of the bonsai trims (cuts) its leaves and branches every year. Every two or three years, the bonsai owner lifts the bonsai out of its pot and trims the roots. Then the owner puts the bonsai back in its pot with some new soil.