Posted by Brent Wilson on 8/29/2016 to Fruit Gardening
Raspberries grow vigorously and need to be pruned yearly. To produce abundant crops of raspberries, proper pruning is important. How you prune raspberries will depend on the type.
Raspberries are classified in various ways: by fruit color and/or fruiting habit.
By Fruit Color
There are red, black, purple, or yellow-fruited raspberry 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 summer-bearing or everbearing. Summerbearing cultivars produce one crop in the early summer. 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.
How To Prune A Raspberry Bush
Raspberry Pruning Terms
If you've never pruned a raspberry bush before, it is very important to understand the terms used to describe various parts of a raspberry plant.
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.
Raspberry Pruning Instructions
At Planting Time
Regarding bare root 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 Or 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', can be pruned to produce fruit once a year or twice a year. If you follow the pruning methods used for summer red raspberries on everbearing varieties plants produce fruit once in spring and once in fall. However, many home gardeners and commercial growers mow or cut all canes to the ground in early spring for the sake of simplicity. Everbearing raspberry plants pruned this way will produce only one crop.
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.
Trellising Raspberry Bushes
Because canes of raspberry bushes are susceptible to damage from high winds, particularly when heavily loaded with fruit, all raspberry varieties benefit from some type of support system. Supports can be an existing fence or a post and wire trellis system, which is very simple to build.
Wire Trellis-Hedgerow System
Raspberry trellises are simple and inexpensive to build. A trellis can help make the crop easier to manage and keep the canes off the ground so that berries are cleaner and easier to pick.
Step-By-Step Trellising Instructions
Sink two 8-foot pressure treated 4x4 posts about 3 feet deep in the ground with about 4 feet of the post above ground at anywhere from 10 to 20 feet apart. In sandy soil you'll need to add a quick-setting mortar mix to anchor the posts.
Using nails, wood screws or bolts, attach two 20- to 24-inch long pressure treated 2x4 cross arms to support wires at the top of each end-post.
Attach a wire securely with u-nails or staples to each end of the cross arm at about 36 inches high for red raspberries and 40 inches high for the black and purple types. Wires can be wrapped one or two times around the post. Make wire as tight as possible.
After having constructed your raspberry trellis, plant the raspberry bushes between the wires and tie them loosely to the wire.