Ours has seen -22f and came out fine last year.

Nice grape. Not very vigorous, very small berry, very early season, whole family loves them. It was all I could do to keep the kids off them until fully ripe.

I would trust the data coming out on Mn, it's a good program.

Thanks Rob

Is your vine exposed or grown on a wall?

My vine is exposed and it survived several days of -20F. I agree, it's not very vigorous. It was bred in zone 4a in northern WI, another Elmer Swenson variety.

Vine is exposed
Actually meant to get another one this winter as the vigor is so low and everyone wanted quite a bit more.