You prune in the fall. If the blueberry bushes have been neglected it can be rejuvenated through severe pruning. Cut these back to the ground leaveing only 2 to 3 inch stubs. The whole bush may be done at once, or half the bush can be done one year and the other half the next year. By useing the first method, the entire crop is lost for one season. The second method allows the plant to bear a poryion of crop each year.