I used to grow Purple Maze here in Central Ohio, and it did reasonably well here. The USDA says I am zone 6, but this past winter, we were down to -28.
Here is a photo of mine from back in 2008, unretouched. My photos are not very organized. If they were I might be able to find a newer photo or one with the scape in it.
edited to clarify that it was this past winter we were at -28, not back when I had Purple Mazeā¦.