Use sharp pruning scissors to cut down all weak and diseased canes to the ground. Recommended time for pruning red raspberries is during March or early May, suggests the Iowa State University Extension.
Inspect canes for any damage and remove all damaged canes to ground level as well.
Measure the vigorous growing canes 30 inches from ground level with the yardstick. Leave only the ones that are about ¼ inch in diameter at this point and cut down all the others.
Prune away all tips on remaining canes that show signs of winter or cold damage. Cut back the stems to the live, healthy stem tissues. The approximate distance between the remaining canes should be about 6 inches at the end of the pruning.
Cut down all the fruiting canes to the ground after the end of the summer harvest. Remove and destroy all pruned material.