One of the most important advances in the blackberry industry was the development of thornless varieties, which need to be trellised. New shoots are tied to the wires with soft string as they grow. Pruning is fairly simple since you keep only 4 to 8 canes per plant. Remove weak canes and suckers. Most gardeners don't leave blackberries on the vine long enough to develop properly.
Berries are sour if harvested too early.
Ripe fruits lose their shiny color and start to turn a dull black. As with raspberries, pick fruit in the morning for better quality. John C. Nye, Dean and Director. Distributed in furtherance of Acts of Congress of May 8 and June 30, 1914. It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age, or national origin.