Q.Do I cut back blackberry bushes back in fall/winter
My blackberry bushes are about 3 years old. Last year I cut them back in the late fall. I fertilized the bushes in the spring and then watered regularly the following spring/summer, but the bushes did not produce any fruit. Are blackberry bushes supposed to be cut back? (note that the previous year they did produce, when I cut them back, but I did not cut them back very far.)

Certified GKH Gardening Expert
Here is more information that should help with pruning your blackberries: https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberry-pruning.htm

Blackberries only produce fruit on the old canes. You selectively prune blackberries if they get to big or to bushy. Just prune some of the old canes back. It does not hurt them to cut them back but you will lose your next years harvest.