Rose of Sharon
I have one rose of Sharon that has green leaves and the other one doesn't. Do some of them start turning green before the other? The one that hasn't turned yet is three yrs. old and the other one is a yr. old.
So you have a plant that isn't leaving out?
Do the branches snap off or bend?
If they snap and break, they have died off.
You can also check the bark for signs of life.
Here are some links with more information.