Does fruit grow on new or old wood? How do I prune them, if any? At the end of the fruit season, do I cut off the long straggly vines or weave them into the trellis? I know to prune the vines that produced this year, but do I have to leave all that length?
The berries form on 2 yr old canes.
To prune remove all but 6 to 12 of the healthiest new canes from each plant, cutting the canes back to the ground.
Wrap the remaining canes around the support.
Here is a link with more information.