Every grower will experience a broken or damaged plant at one point or another. At first glance, a broken limb or branch on a bonsai can appear to be a repair challenge. Before panic begins, remember that the bonsai is a tree, and all trees encounter a broken limb or two in their natural environment. Very much like their full-size counterparts, the bonsai tree usually can overcome its damage with some general assistance and care.
Trim away and discard any broken limbs on the bonsai tree using sharp, sterile scissors. Trim with a sharp, blunt cut to promote healing.
Repair limbs that are split but remain attached by a layer of outer bark (cambium layer). Clean the broken limb with a clean, damp cloth. Apply a small drop of conventional superglue to the broken wood. Hold the branch in place for several seconds while quickly wiping the excess glue from the bonding edges.
Allow the bonsai several weeks to heal the branch. Maintain the regular care, irrigation and fertilizing schedules. Delay immediate pruning schedules for approximately four to six weeks.
Remove the bonsai from its container. Carefully inspect the bonsai and its root system for any broken or shattered container pieces. Repot the bonsai if the damage includes a broken pot with an exposed or damaged root system.
Gently remove the excessive soil from the root system. Avoid pulling or tugging the roots to prevent further damage. Trim the root system with sharp, sterile pruning shears or scissors. Remove damaged or broken roots with a sharp, blunt cut. Trim away any wilted or dying roots. Trim no more than 1/3 of the entire root system.
Repot the bonsai in a container with a good drainage system. Incorporate 2/3 nutrient rich soil with 1/3 organic compost. Line the bottom of the container with a layer of soil. Center the bonsai in the container and fill with the soil. Ensure that no roots are exposed. Press the soil firmly around the bonsai to secure its position.
Irrigate the bonsai to promote a good re-establishment. Fill a sink with tepid water so that the water level rests about 1 inch past the bonsai container. Place the newly-repotted bonsai in the sink. Allow the bonsai to rest until the bubbles no longer rise to the surface. Remove the bonsai from the water and allow it to rest until water no longer drains from the bottom of the container.
Position the newly-repotted bonsai in a warm location that receives about four to six hours of partially shaded sunlight each day. Choose a location with good air circulation and keep the bonsai away from direct heat sources, such as heating vents and air conditioners.