'Bonfire' is a Salvia splendens variety and not Salvia coccinea. As such, it will only be hardy in zones 10-11. Technically, it is a perennial but in most areas it is "used as an annual." You can save seeds, though. If you have a greenhouse you could overwinter them but it's probably too much bother for something that's really common and easy to grow from seed. Salvias tend to be pest magnets when overwintering.
