Where are these growing?
Almost looks like damage caused by a piercing insect... (like a weevil or something)....or maybe a snail.
Rose of Sharon are tough, I never worry about mine...
I have one that is slowly growing new leaves after shedding them in June (too dry).
Silliest thing, it kept blooming with no leaves!
The rest of them didn't get any water either, but held on to their leaves....
