|I have ever-bearing raspberries, which I have just pruned down to about six buds. A few years ago I put in thorn-free blackberries. These seem to grow differently; how do I prune them?
|Raspberry, blackberry and their relatives are usually referred to as the brambles(Rubus). Brambles are woody biennials. The canes(branches) that is. The roots are perennial and because of that the roots will live for a VERY long time. Each cane sprouts from the roots and will grow to it's full height in a season. The following year it produces fruit and promptly dies. While that's happening, other canes are growing which will produce fruit the next year.
This tells you that you need to prune out all the OLD canes and leave the ones that grew during last summer since they will bear fruit this year. It is relatively easy to tell the old from the new canes. The old ones look gray and scraggily where the new ones look vigorous, reddish green and young. Also, remove any weak, spindly new canes at this time. Whether they have thorns or not makes NO difference, until you go to pick them. At that point you'll wish they were all thornless!