Answer: Black spots can be anything from insects to frass (bug poop). If you can brush the spots off the flowers and leaves, it's frass and indicates that your rose of sharon has a population of little green caterpillars feasting on the flowers. Dipel (bacillus thuringensis) will control the pests. If you cannot brush the spots off, they're insects. You will want to collect a few and take them to your local nursery for identification. Helpful folks there will make control recommendations based upon which pest you're dealing with. Best wishes with your rose of sharon!
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