The prime ark 45 has thorns but seems slightly stronger than freedom which is thornless. This is my heirloom Blackberries by the gallons . @39thparallel has trialed these and traveler and has an extra year of experience growing them. He suggested the varieties to me and I shared my heirloom field variety with him that does very well in this area. We are all here to help each other out so just let us know if we can help with scion wood etc. @39thparallel and I go in on rootstock orders /trade scion wood etc. Once in awhile and I buy trees from his nursery.The prime ark thread is here Extending the blackberry season