I have a few rose of Sharon plants in my yard. They were there when I moved in. I haven't touched them because I haven't known what to do with them. They are more like trees at this point than bushes. They have a trunk and just a few branches. I didn't understand what the fuss was about them until I saw a "bush" in full bloom and realized, hey, I have those in my yard, but they don't look like that! How can I get the tree back down to a managable size and prune it so it will bush out instead of growing vertically? I'm not experienced at pruning so don't know when to do it or how far back to cut it. Thanks!