Rose of Sharon is usually reserved for application to Hibiscus syriacus - which this plant is NOT - but is also sometimes applied to other types of hibiscus. At a guess, I'd think this could be some form of Hibiscus acetosella, which typically has red tinted foliage and often produces Japanese maple-like leaves but is treated as an annual in colder climates. Or possibly one of the moscheutos hybrids.