Every time we'd go to Florida, I'd be enthralled by the tropical hibiscus (Hibiscus rosa-sinensis) in bloom. So many vibrant colors grabbed my attention every time we'd pass by them when walking or driving just about anywhere. Sadly, I knew we couldn't put them in the ground here in Ohio and expect them to live through the winter.
But that didn't mean I couldn't have hibiscus in Ohio. I could keep them in containers and take them in and out of the house as the weather dictated. Two winters ago, I bought a hibiscus plant for two dollars when we were in Florida and I brought it home on the plane. It survived the rest of the winter with a southern exposure in the house and then I planted it in the ground, pot and all, when night temperatures reached 50° consistently.
It bloomed beautifully for me, both the following summer and even most of the winter while it was inside. Then as spring approached, something happened and it suddenly died. I suspect I forgot to water it one too many times. Usually I overwater, so I'd been trying to not do that and I fear I went to the other extreme and the hibiscus didn't survive. For two dollars, I sure got a lot of enjoyment out of it anyway.
But there's a way to enjoy hibiscus in the north without all that in and out business. There are two hybrid hibiscus that are hardy to our zone 5 winters: Hibiscus syriacus and Hibiscus moscheutos.
The easiest way to tell if a hibiscus is hardy for us here is to look at the leaves. If they're glossy, it's probably tropical. Last week, Kara and I went nursery hopping to see if there were any late season bargains to be had and we found some gorgeous tropical hibiscus at KMart for $5.50! They were lush and healthy and came in nice-looking square pots, too. Kara bought one and I bought two to put on each side of the pool steps.
I'll bring them in this winter and attempt to keep them going until I can put them outside next summer. The gorgeous citrus blooms scream "Florida!" to me and they're worth the extra effort to try and overwinter them.
Last year, I planted two Hibiscus moscheutos, which are hardy. They have ginormous blooms measuring 8-10 inches across. This hibiscus dies all the way back to the ground after a hard freeze in the fall, and begins growing again in late spring.
I also planted four Hibiscus syriacus, also known as Althea or Rose of Sharon. The blooms are similar to other hibiscus, but are much smaller, being approximately 3-4 inches across. These do not die down to the ground after frost, but they do lose their leaves. They too are rather slow to break dormancy in the spring, so don't think they've not made it through the winter just because they're later than most plants to show signs of life.