Summer Care of Raspberries

Raspberries are available in red, yellow, purple and black. Red raspberries are the most common and most easily grown. The varieties we grow originated as hybrids of American and European red raspberries. Yellow raspberries - really amber in color - are essentially the same as red raspberries in both habit and culture. Black fruited raspberries originated from the American black raspberry and have a different growth habit than the red raspberries. They are not quite as hardy and generally considered more difficult to grow, although if grown properly they can be more productive per acre than the reds.

Purple raspberries are hybrids between red and black raspberries. Similar in growth to black raspberries, purple raspberries, however, tend to be more vigorous and slightly hardier. Proper pruning of raspberries is related to harvest time. The canes of raspberries are biennial. This meant, they produce their growth during the first year, but do not flower and fruit until the second year. After canes have fruited, they die. The roots, however, are perennial and send up a new crop of canes each year while the old canes are flowering and bearing fruit.

Old canes should be removed promptly after fruiting. Their removal may be delayed until spring, but it is much easier to work among the young canes when they are small, and when new canes may be easily identified from those that have just finished fruiting. Disease control is another reason for prompt pruning. A disease called anthracnose is the most common raspberry problem. Prompt elimination of old canes helps reduce spread of this decease to new canes.

Pruning also allows better air circulation as well as making thorough spraying for disease control easier. Anthracnose can be identified by the grayish spots it produces on steams. These spots enlarge until the entire stem may be killed.

During late spring and summer, black and purple raspberries need pruning not required by red and yellow types. When the new shoots desired height, their tips should be pinched back 3 to 4 inches. Black raspberries should be pinched back when new shoots are about 24 inches tall, while purple raspberries should be pinched when they reach 30 to 36 inches. When grown on supports, they may be allowed to grow 6 to 8 inches taller before pinching. Also, old canes of black and purple types must be removed after fruiting. Although pinching is not needed by red raspberries, a different technique is needed.

http://en.wikipedia.org/wiki/Raspberry