I have a patch of raspberry primocanes, about 30 feet by 10, here in S. Korea. They were a wild bunch when we moved in 2 years ago and I'll be trying to get some fruit next year.

I cut back the few floricanes in August.

The first frost is due in about 2-3 weeks.

Should I prune back drastically now? I want to make some space and support the canes so I can get access next year, as they're all growing together in profusion, but I don't know when and how much to prune back.

Also, could you tell me if and when I should add manure?

Many thanks