It depends on what type of hibiscus they are. There are both hardy and tropical hibiscus. The hardy ones will get along fine with no help from you, while the tropical ones will die outside over the winter no matter what you do.

Did your hibiscus come with any labels? If you know their variety names, we can tell you whether they are hardy or tropical.

My hibiscus plants are the hardy variety. However, there was no information on the winter care of them on the plant guide that came with them.

Okay -- if they're hardy hibiscus, then just let em go to sleep. I personally don't mulch or cut back til spring, but I don't know whether it would make a difference one way or the other.

Hardy hibiscus are VERY late to sprout in the spring, so don't despair when they are about the last things to show up next year!