More selections in the US...here another one.
Just not sure if the hardiness is what they say...

Here is a link that might be useful: Stenulson Blackberry

Would be nice if there was an intensive gathering and testing of the hardiest and most desirable of wild blackberry selection and their hybrids to determine the best of the lot for growing on the Canadian prairies.

Woodstock no longer shows the Stenulson Blackberry on their website. Maybe if you called them, they might have some. All they list are Darrow. Northwoodswis

I'm not sold yet on the zone 3 of the Stenulson,..they also list Darrow as zone 3, which it is not! Darrow is listed around zone 5 or 6 normally.