These brambles bear fruit on branches growing from canes. Stimulate branch growth by pinching out the tip of any new cane when it's about 3 feet tall. Not all canes reach that height at once, so prune the patch a few times during the summer. Sometime during the dormant season, prune the pinched canes again, shortening all the branches back to 4 to 18 inches. This allows sturdier branches to bear more fruit.
Blackberries Cut away old canes and reduce the number of new ones.
Trailing blackberries are usually trained to a trellis. After pruning, allow each season's new canes to trail on the ground, where they won't crowd fruiting canes. Alternatively, train new canes on one wire or in one direction along the trellis, and train fruiting canes along the other wire or in the other direction. Red and Yellow Raspberries Fruit stalks grow on the canes, not on branches. Longer canes produce more fruit.