Blackberries are my favorite berry. But not the kind of sour grocery store variety. At my childhood home, the back fence was lined with blackberries. I loved them. We would stand out there for hours, during the summer, picking and eating blackberries. Most people know that blackberries start out red, and then turn dark purple/black as they ripen. But to get them when they are perfectly ripe and sweet, the key is to wait for them to change from shiny to dull. The window for this perfectly ripe blackberry is a day or two, and they won’t travel well, so you will only get these beauties if you are picking them yourself.
My mother would turn them into pie, and jam, and sometimes ice cream. I was so spoiled that if they were picked and brought into the house, out of the sun. I wouldn’t eat them. And now I have them, and they are doing quite well.
All this nostalgia is great, but my point is, everyone should stop being afraid of planting blackberries. We have never had problems with cultivated blackberries being invasive. Cultivated blackberries don’t send out runners, raspberries are more prone to that. The vines will root, if allowed to touch the ground, but it takes awhile. If you don’t want that just cut them.
That being said, I have had issues with wild blackberries, usually spread by seed by birds. Unfortunately, the wild blackberries around here, don’t even taste good. They are extraordinarily bland.