To produce abundant crops of raspberries, proper pruning is important. How you prune raspberries will depend on the type. Raspberries grow vigorously and need to be pruned yearly. Pruning practices depend on the type of raspberry grown. Raspberries are classified in various ways: by fruit color and/or fruiting habit.
By Fruit Color - There are red, black, purple, or yellow-fruited types. The red raspberry is first to ripen, followed by the black, purple, and yellow cultivars. Compared with black raspberries, red raspberries tend to be more cold hardy, have larger berries, and have more erect canes. Black raspberries are less cold hardy; have smaller, seedier, and more aromatic berries; and have arching canes. Purple raspberries are hybrids of red and black raspberries and tend to respond in growth habit similar to black raspberries. Most yellow raspberries are similar to red raspberries in growth habit.
By Fruiting Habit - Raspberries are also classified as summerbearing or everbearing. Summerbearing cultivars produce one crop in the early summer, while everbearing cultivars can produce up to two crops a year, one crop being produced in the spring and the second crop in the fall. Most everbearing raspberries are of red or yellow type.
Raspberry Pruning Terms
It is very important to understand the terms used to describe various parts of a raspberry plant before attempting to prune raspberries
Cane - The shoots (vertical branches) that grow out of the ground.
Primocane - These are new, first year canes that emerge from the ground.
Floricanes - These are two-year old canes that bear fruit.
How To Prune Raspberries
At Planting Time - When planting bareroot raspberry plants, cut them back to about 6 inches above the ground at planting time. Container-grown plants do not usually require this type of pruning at planting time.
Summer-bearing red and yellow raspberries: After the last harvest, cut all canes that have produced fruit to ground level and remove them. This eliminates a disease source and gives primocanes (new canes that didn't bear fruit) more room to grow. Thin primocanes to 4 to 5 sturdy canes per foot of row. In areas where winter injury is common, you may delay thinning the primocanes until the following spring, when you will be able to tell which canes have survived. Primocane growth may be somewhat less under this delayed-thinning method, due to competition among new canes. Before growth starts in spring, cutting the canes to about 12 inches above the wire is desirable. Don’t cut back more than 25% of each cane, to avoid reducing yield.
Everbearing Red Raspberries: Everbearing red raspberries, such as "Heritage" raspberry, can be pruned to produce fruit once a year or twice a year. If you follow the pruning methods used for summer red raspberries, "Heritage" raspberry will produce fruit once in spring and once in fall. However, many home gardeners and commercial growers mow or cut all "Heritage" canes to the ground in early spring for the sake of simplicity. "Heritage" raspberry pruned this way will produce only one crop.
Fall-bearing raspberries: If only a fall crop is desired, cut all canes off at the base before growth begins in spring. Fruit will be produced on primocanes in late summer or fall. If both fall and summer crops are desired, thin the canes as described for summer-bearing raspberries. The primocanes that produced the fall crop should not be removed, as they will produce fruit the following summer. Prune them back in spring to about 12 inches above the wire, or to the last visible node that had fruit, cutting off the dead tips.
Black and purple raspberries: Black and purple raspberries are pruned three times a year: in the spring, summer, and after fruiting.The first pruning is done in early spring when lateral (side) branches are cut back to 8 to 10 inches in length. The second pruning involves using your finger tips to pinch off the top 2 to 3 inches of the tips of new primocanes during summer. When grown without supports, this tipping is done when black raspberry canes reach 24 inches in height and when purple types reach 30 inches. The third pruning involves the removal of canes that produced fruits, right after the harvest.
