Nearly every tip has rooted on 4 ft+ canes. First year crowns planted last year. 1.) Prune them to 24"? 2.) relocate the new crowns from tip ones back into row? 3.) For the tips that didn't root...after pruning, should/could I plant those too? 4.) Can I plant early peas next to vines for compatibility, bee attraction and nitrogen fixing? 5.) I've read they are self-pollinating... do bees pollinate too?
Erect Blackberry Pruning
Certified GKH Gardening Expert
These articles will provide advice on pruning erect blackberries:
I'd say it's best to relocate the new crowns that have grown back into the row. This will allow you to have a neater planting that will be easier to pick from in the future.
Using the pruned tips as cuttings to plant should work too. You could also try "tip layering":
Peas are known as good companions for blackberries, so go for it! It is a good idea to use peas (or other nearby plants) to attract bees. Blackberries will be somewhat self-pollinated (by the wind), but bees also pollinate them and will help your plants produce more and better fruit: