Question: When do I trim back blackberry bushes, this was my first year with planting the Chester's last spring (we had no fruit this year) - Glen
Answer: Glen, I see I need to take time to write a more detailed article on berry pruning (later). For now the quick answer with links to others.
Chester fruits on second year wood (Floricanes). This means the new growth that you see this year will produce the fruit for you next year. So do not prune off this growth until after it fruits next year. Once the cane has fruited, it can be removed since it will die anyway.
Here are some helpful and more thorough links: