Does anybody have a hardy gardenia variety that survived and preferably has thrived through this past winter around the Washington DC area? I'm looking for one with a lot of fragrance.

I know most varieties are marginally hardy in the Washington area and I'm on the cold end of the Washington zone, since I have very little concrete or black top to hold heat in my area. In addition, I want to grow it in a great big pot on my deck, the only place I have full sun, so even a little more hardiness would be good.
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