When we moved in last year, she and I chatted about the raspberries growing on the line between our properties. "Should I cut them back?" she asked. Uh...you're kidding, right?
No. Do not cut them back. In fact, if you have any especially powerful fertilizers, pour them on. I have no objection to Unobtainium, Kryptonite, or any other magical stuff, either.
This year, having watched the canes hungrily for months, we're harvesting bowls of raspberries every few days. It's fantastic. I've planted new raspberry and blackberry plants along the border of my vegetable garden and I will probably put in more next spring. Because you simply cannot have too many berries.
But even now: wow.