Rose of Sharon are nearly impossible to kill. we started out a few years ago with a few 2 or three inch tall root sprouts. we now have hundreds many 6 or more feet tall.
Yes, I do agree, Rose of Sharon is a tough plant, but in order to transplant with the least amount of stress to the shrub, it is better to allow it to go dormant. Better root system developement and better plant performance in the long run.