It happens to everyone! Failure to rotate your bonsai brings about troublesome results. You may be positioning your bonsai, in this case Satsuki Azalea “Kaho”, next to the backyard fence with shade trees. The location gets inadequate sun light. The morning sun is blocked by the neighbor’s shade trees and the six foot high fence. The only sun light on that location comes in the mid to late afternoon. By not rotating the Satsuki Azalea bonsai often enough, the back side of the tree fails to get sufficient sun light. The leaves shrivel and die off on the side without the adequate sun light. By rotating the bonsai frequently, at least once per week, sun light is present and leaves receive a good balance of sun light for healthy growth. This will elevate parts of the tree getting weak.
The Golden State Bonsai Federation (GSBF) Golden Statements Magazine is free and online live.
Here is a direct link to the Golden Statements Magazine for your reading enjoyment.