Root-bound

A bonsai is root-bound when its roots have grown so much that they fill the pot and have no more room to expand. This can cause several problems for the health and appearance of the bonsai, such as reduced water and nutrient uptake, stunted growth, poor drainage, and root rot. Root-bound bonsai may also become unstable and topple over easily. To prevent these issues, it is important to repot the bonsai regularly and prune the roots as needed.