It is an H. moscheutos hybrid, possibly Southern Belle, but there are a lot that look very similar.

It's not a tropical Hibiscus and is hardy in the ground to about zone 7.

My best guess is it is called Lord Baltimore. It is hardy to this zone. I looked at the leaves behind your flower and can comfortably say that it is Lord Baltimore. It is not a tropical plant. I hope I am right. Indu

Thanks for the help. I was worried it may not survive the winters here.

I'm not familiar with the plant but if it is grafted and the plant freezes below the graft, you might not get the same flower again. I once received a hibiscus that had beautiful, dinner plate size yellow flowers. After a frost, the flowers on it were small pink ones.

Regina