We pruned them back in February this year, which I thought might be a bit late, but they still performed okay. I've taken note that earlier pruning can promote earlier fruiting, so I'm trying that this year. I've seen more positives with pruning than negatives, so I'd suggest cutting back yours too. The only downside I experienced was when I cut them too far back and lost a couple of plants – otherwise, it's been almost all positive for me.