Oh my! You are so ready to be defeated, you are already accepting it, and it hasn't happened!!
I'm not sure that Chad meant "tough" in the same way you took it. I think he might have been telling you that it was a pretty tough plant and could take it.
I'm seeing many of the same problems with this plant, as I saw on your roses, and I think if you try the things I have suggested for your roses on this Rose of Sharon, you will see it pick up as well.
You might also want to take a scan through the other forums, as there are quite a few threads that deal with Rose of Sharon plants, and they may give you some ideas.
Also, I'm not sure that I mentioned it in my reply to you in the rose forum, but you should probably check the ph of your soil in several different parts. Roses should be at a ph level of 5.8 - 6.8, while Rose of Sharon prefer it to be between 6.1 and 6.5. It make a lot of difference if you have a plant in soil that is too acidic or too alkaline for it's liking.
Hope some of this helps - and don't be so ready to accept defeat!! It's all a learning process - something we all keep doing every single day!