Koyo Satsuki Azalea in training

It has a styrofoam diaper/ pot to insulate the kanuma pumice soil and keep the roots cooler.  This one is likely 50+ years old and with amazingly multi-colored blooms, which will likely open in May.  Just search my “posts by category” pull-down to the right of the webpage and look for “Koyo Satsuki” to see what the best bonsai material in the world can look like.  Satsuki bonsai are the king of bonsai!