I am wanting to expand my little blackberry business, but the kind of berries that I have has the WORST thorns! I was hoping to try a different variety, but most of the "hardy" THORNLESS blackberries offered are only hardy in zone 5. We live on the border of zone 4 & 5. I was hoping that my fellow Midwesterners with blackberries could tell me what has done well for them. Also, when you want more bushes, do you dig up the roots (like I have been doing), or do you take cuttings?