Definitely a hardy hibiscus cultivar. Kind of looks like it could be 'Luna Pink Swirl' like Jay stated, or possibly the 'Disco Belle Pink'. Looks like it is doing quite well up there in zone 4. If you like it, there are quite a few hardy hibiscus that do pretty well up there in that area, such as 'Copper King', which is one of my favorite hardy varieties with it's dark leaves.