There are several different varieties of raspberry plants and horticulturists classify them according to the color of the berries and the way they bear fruit. Raspberries may be red, purple or black, with some producing one harvest of berries per growing season and others producing two harvests of berries. Black raspberries are small, richly scented berries with plentiful seeds. Gardeners must prune black raspberries three times per growing season.
Prune black raspberry canes for the first time in the spring prior to summer growth beginning. Use the pruning shears to trim off all lateral branches so they are 12 inches long. Remove smaller lateral branches so there are not more than five sturdy lateral branches on each plant.
Watch the black raspberry canes as they begin to grow in the summer. When the new raspberry canes reach 24 inches tall, pinch off between 2 and 3 inches of the newest growth. Gardeners refer to this second pruning process of the growing season as "tipping."
Cut all of the canes that bore fruit down to the soil level immediately after you harvest raspberries for the third and final pruning of the growing season.