Growing up my grandmother has lots of Rose of Sharon as these were called back then. They were heavy in the seed category therefore spreading all over the yard. These new refined Rose of Sharon do not spread in the invasive way that old varieties did. Plus, the flowers are much prettier and have more interest. I'm now using these plants in some of my landscapes for their summer blooms. Very nice!
Hibiscus syriacus makes for good tea and food, among other usages such as cordage or medicine. There is information readily available for this species, as well as recipes. Please do your own research, and consume or use at your own risk. Expect mucilage from this okra relative.