Hardy hibiscus do very well in my garden year round.

That's great! I would love to plant my hibiscus outdoors as well.

How would I tell if my plant is also hardy?
Also, how do you prevent it from freezing /dying in winter?

There are tropical hibiscus and there are hardy hibiscus. Only the hardy varieties will survive outside in Maryland. What color are the flowers? Sometimes you can figure out which you have by matching the flower color to variety. Also where and when did you buy it? If you bought it in the grocery store or a big box store in bloom in the winter/spring, chances are it is a tropical hibiscus.

About ten years ago or so, there was a breeding revolution that produced tropical hibiscus that would bloom in a 4 inch pot. This brought about lots of sales as a house plant. Again, if you bought it in bloom while in a four inch pot, it is probably a tropical hibiscus.

Ah, unfortunately in that case mine is a tropical variety.

Would local nurseries have hardy varieties?

Thanks!

Yes, larger nurseries in Maryland often have hardy hibiscus. Just be sure and check the hardiness zones on the variety you are looking at, because they are often mixed together by seasonal employees who think "hibiscus: they all go over there together"--without realizing some belong in the summer patio plant/house plant section and others in the landscape plant area.

I've found hardy hibiscus are full sun plants allthough some are marked part sun.

Rose of Sharon work in part sun but lean.

Even Home Depot has hibiscus--hardy moschata or the rose of sharon that's called hibsicus in some regions.