I have wintered Jewel and Mac black in zone 3 with no damage . Not a bad winter last year or this . -33 or so . I planted a Niwot start there last may . It did ripen some berries in October . Summer place so I will see in June how or if it survived . I suspect black raspberries are hardier than listed .

I decided to forego the purchase of 'Ohio's Treasure' on the account that I had been unsuccessful with both 'Jewel' and 'Munger'. Winters that can at times can be six months long combined with early autumn frosts winnow out only but the hardiest! Though, I am gonna give 'Purple Dream' a try.

I'm curious to know if they make it in your climate. This is apparently a new cultivar released only a couple of years ago. I have both Munger and Jewel to try out this year.

'Purple Dream' (from Whiffletree Nursery) had arrived as nice decent plants with an extensive root system, they're now starting to kick into gear and one carries a few flower buds. I'll update this as time passes.

That's also a new variety for me, both seem to be everbearing. Here's a link to Ohio's treasure's patent, it's an interesting read.