In Britain I would have said that it was due to lack of sunshine (cloud and rain for weeks now). USA, I don't know, sorry.

FYI, I have blooms. They just won't open! Could the ants I see have anything to do with it? This is the first time I have had one. It does stand between shrubs rather than by itself. So it does get shade from the plants beside.

I believe that this is very common with this shrub and some say it is just the plants way of saving energy, a bit like apple drop in apple trees so only a certain number can ripen.

But causes can be waterlogging of the roots caused by poor drainage or , similarly, overwatering.

I suspect that none of this solves your problem.

If you Google " Rose of Sharon buds wont open " you come across lots of articles and they all seem to be from the USA .