HIbiscus is a tricky genus. The most common plants you will find a

Tropical hibiscus- (H. rosa-sinensis) These are not hardy and are
mainly sold as house plants in your area.

Perennial hibiscus- (H. moscheutos and the less common H. coccineus)
Both are hardy to zone 5 and have the same size flowers as the tropical
kind.

Rose of sharon (H. syriacus) Often sold as "althea" or sometimes
"hardy hibiscus". This is a woody shrub with much smaller flowers than
the above mentioned, but essentially the same appearence otherwise.
Hardy to zone 5, but bad winters can do them in sometimes.

Hope this helps! Searching google images with the botanical names will
probably turn hup lots of pictures.

Toad