Ideally, it is a good idea to remove the canes after fruiting to lessen the chance of the old canes developing disease in them but if you are not sure of what to remove, just leave it as is until the Spring. The old canes will turn brown and die. You can remove them then usually without any serious consequences.

Cut the canes that have fruited last summer. You will get fruit this coming summer on the canes that grew last year. It is also recommended to pinch the tips of any new canes which will be growing this year at 1 or 1,5 meters to stimulate the growth of side shoots where the berries tend to form. So more side shoots more berries.

OK, thanks, will do so.

I'd like to jump in here and ask a similar question. Every year I have the same dilemma, I can't tell which canes fruited and it's not that obvious this late which ones are new from this past year. Is there a surefire way to distinguish from old canes that don't look dead, and newer canes that don't look new.

I'm glad to see the advice that one can wait until spring when the old canes will be obviously dead. But it would be nice to be able to sort them out in the late fall/early winter.

jbclem - I agree it's sometimes hard to tell old from new canes until you've had a bit of experience. To get around this you could prune out the fruiting canes at the same time as you harvest the last of the berries.

All of the uncultivated blackberry canes around here still have the old dried up fruiting clusters on them--those would be the ones to prune. Evidently many of these canes in gardens lose this distinguishing feature. If during winter the old and new canes cannot be told apart, pruning now is a moot point. Wait until late spring to see what blooms and prune out the rest then, being careful not to damage the emerging protocanes. If the only practical time to prune is in the winter, put a marker on the fruiting canes during harvest, this should only take a few seconds per cane. If you have an old row of raspberries with hundreds of canes, good luck with that.

Just wondering... how does the flavour of the fruit compare with a thorny blackberry? I have heard that the thornless isn't so good.

The only dried up fruit on mine is on the primocane-fruiting varieties which are not the ones you should prune, so keep that in mind if you think you might those planted. There's more flavor variation on one plant from the various degrees of ripening than you will find between many of these varieties. With that said, the Western trailing blackberries, like Marion, taste much better to me than the Eastern blackberries, thorny or thornless. Triple crown and Osage are the Eastern varieties that I think taste the best and both are thornless.