Question
I have a double rose of sharon that is about 15 years old.  It's about 5 ft across and at least 8 ft tall.  It has many many blooms however very few actually open.  They remain tightly closed and turn yellow.  What's causing this?  The bush/tree is in a garden surrounded by pine mulch.  I've never watered it (except when it was new) and never applied any type of fertilizer, other than an occasional drink of Miracle Grow.  It has a huge woody trunk and the leaves are normal looking.  Any ideas?  Thank you!

Answer
I only answer questions about roses but I like the Rose of Sharon so here are some suggestions about what may be causing the bud drop problem.
It may be caused by gall midge. Place some buds in a plastic bag. After a day or two, you may see the very small yellowish worm-like larva on the plastic. Control the midge affecting buds with Orthene sprays as needed. Also Aphids are a problem on new growth. The shrub is also susceptible to spider mites in hot, dry locations. Other problems include leaf spots, blights, Japanese beetle, and white fly. I would take a piece of white paper, hold it under a bud, hit the bud and see if any bugs drop off. If there is an insect on the paper then that is the one who is causing your problem. The spray will get rid of them for you and the plant will start to bloom again. Hope this helps.