Repotting is a vital element in maintaining the health of the bonsai tree. The objective of repotting would be to get rid of excess roots that could cause the tree to purge, or not get enough nutrients because of its mass. Repotting also makes certain your tree may continue to flourish within a little pot. Bonsai trees must be repotted once every two to five decades, based on how fast your bonsai tree develops.