They should be trimmed right after they finish blooming. Here is a link to info about pruning trees and shrubs. http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/pruning-trees-shrubs/
Is it too late for this season? We want time for it to recover.
We harvest the berries to make jelly so prefer to wait until after the fruit is ready.
They bloom on the new growth from the previous year so that is why you need to prune right after blooming, otherwise you are cutting off the blooms for next year. You may have to forfeit some fruit in order to create the shape you are wanting.