... do you prune them?

The variety I have - Illini - would probably get ten feet tall if they didn't fall over sideways first.

They're vigorous, winter hardy, and ... SOUR!

But seriously, should I be pruning them to keep them "in bounds"?

I can't help you but will keep watching as I just planted 3 last year.

We dont prune ours, neithre does my mom. Maybe we should?

They grow rampantly wild in Oregon. We don't have to plant them!

We have pruned them back, but only 1/2 at a time. It seems like we didn't get berries off of the newer growth.
Our bushes if not pruned, the stalks get very large and woody, and the thorns are huge.

Ours are growing wild in the neighboring lot (hope noone ever buys it!). The deer get most of them! The rest we seem to eat as we pick!

You PLANT them??? LOL

Our entire back yard would be taken over in one summer if we did not hack them back every week. I bet our house would be covered after 2 years.

They grow new branches every year to bear fruit, so cutting them back is probably a good thing. If you insist on "growing" them.

Seriously, you can walk down almost any street around here and just eat as you go when the blackberries get ripe.

My husband grows one in a huge pot and yes prunes at end of season...We do get blackberry's as we eat them as we pick them...just a snack...
I guess a seed dropped and a vine started under our deck so I just transplanted into the garden...Hoping it takes off but by the sounds of it I might regret that.