How do I tell which type of hibiscus I have (i.e. hardy or tropical)?
Tropical Hibiscus are an evergreen that keeps it's leaves year round.
They are hardy in zones 9 to 11 and need to be moved indoors for winter in colder climates.
Hardy Hibiscus are deciduous and drop their leaves off in Winter. There are over 200 species of hardy Hibiscus.
Most hardy Hibiscus can grow in zones 4 and above.
These plants winter over outdoors and are generally planted directly into the ground.
Here are some articles with more information.