This is Why Kiowa Blackberries are the Best Berries to Grow May 17, 2020

Kiowa makes huge berries.  Yes, the canes have lots of thorns.  But I've grown a thornless variety, and in my experience the plants just sort of disappear over time.  You look up one spring and there are none growing anywhere.  But Kiowa persists.
Blackberry brambles are hard work.  You have to remove the old canes.  If you don't get in there with loppers and hand snips every year and cut away the old canes, you will really end up with an un-navigable patch of pain. Blackberries grow on year-old growth.  The new growth is springing up right when you are picking the berries from last year's growth.  As soon as all the berries have been picked, there is no sense in waiting, you can get in there and cut away the canes (before it gets too hot).  I never do that - I procrastinate until it is 100 degrees outside, but it's good advice nevertheless.  Maybe I'll take my advice someday.