NC State Extension Publications

General

All blackberries and raspberries must be pruned and trained. Floricane-fruiting caneberries need pruning several times a year. Primocane-fruiting raspberries need to be pruned (mowed) only once a year during the winter.

Erect Floricane-Fruiting Blackberries

During the first year, plants establish root systems and a moderate number of canes. Their growth habit in the first year can be trailing, like a dewberry. Attach these flexible canes to the trellis by wrapping the canes loosely to the wire and then tying them to the wire. Growth of the primocanes in the second and subsequent years will be erect. To properly train erect types, allow the primocanes to develop in a row approximately 12 inches wide at the base during the growing season. Most newly emerging primocanes will grow in the center of the row. While these primocanes are still flexible, encourage them to grow up in between the two sides of a T- or V-trellis by pushing them into the center of the row before they reach the trellis’s bottom wire. When the new shoots of erect blackberries reach 8 to 12 inches above the top wire, they should be tipped. Tipping encourages the growth of laterals on which fruit is produced. Use your fingers to pinch off the tender new growth at the tip of the cane—known as soft tipping (Figure 12). Later on, use loppers or a mechanical hedger capable of making a clean sharp cut, known as hard tipping (Figure 13). Tipping or hedging can lead to cane blight disease, Leptosphaeria coniothyrium, especially if the cuts are made just before a rain event (Figure 14). Soft tipping early by pinching young growth invites less disease than hard tipping. After tipping, apply a preventative fungicide to protect cuts from cane blight. The Cane Blight of Blackberry factsheet contains more information about this disease.

Tipped canes will grow stout and be more capable of supporting a heavy fruit crop the following year. In southern Georgia, many thornless cultivars produce only one to three large primocanes each year. In this case, tip the canes during the summer when they attain a height of 2 to 3 feet to encourage branching.

After fruiting, remove dead floricanes and thin out weak primocanes as time permits. In late winter, prune the laterals to 12 to 18 inches if needed. Pruning will increase air, sunlight, and spray penetration within the row and make harvesting more convenient and result in larger berries. Where large-diameter pruning cuts are made, stem disease has been severe in some years. A fungicide application after pruning is recommended. At the same time, remove any remaining dead and weak wood. Leave only about six to eight healthy, vigorous, evenly spaced canes spaced per linear yard (3 feet) of row. Erect blackberries must be trellised for additional support and for ease of harvest. Follow the trellising guidelines for trailing and semi-erect types using one of the trellises described in the Trellis Systems section of this publication.

Figure 12.

Figure 12. Small diameter tipping can easily be done by hand. The resulting wound is smaller and is less susceptible to disease infection.

Phil Brannen, Univeristy of Georgia

Figure 13.

Figure 13. Larger diameter cut made with pruners. The wound is larger and the cane is more susceptible to disease infection.

Phil Brannen, University of Georgia

Figure 14. Cane blight of blackberry.

Figure 14. Cane blight of blackberry.

Gina Fernandez, NC State University

Semi-Erect and Trailing Floricane-Fruiting Blackberries

During the first growing season, tie semi-erect and trailing blackberry primocanes to a trellis to allow weed control under the vines. After the first season, all types of blackberries must be trained on trellises to assure clean, disease-free fruit and easy picking.

During the second season, before buds swell, bring floricanes up to the trellis wires and tie them individually with soft string or plastic tape from a hand-held device designed for tying caneberries and grapes. At the same time, prune the lateral branches to 10 to 12 inches in length. If 3 feet or more of growth was produced the first year, cropping can occur in year two. If only a small amount of growth was made the first year, cut the canes back to within several inches of the ground. This practice helps the plants become better established by preventing a severe stress on their productivity from fruiting and favors the development of sturdier, more fruitful shoots in the subsequent year. In the succeeding years, new shoot growth will be more vigorous.

Primocanes of trailing and semi-erect blackberries are extremely vigorous and need to be managed throughout the summer. Tie primocanes loosely together as they develop, and train them up through the plant to the top wire. Once they have reached the top wire, divide and tie them to the wire. This method is well suited for semi-erect and less vigorous trailing cultivars. Place plants close together and place canes uniformly over the trellis to maximize light exposure and yield.

Primocane-Fruiting Blackberries

During the late winter or early spring, remove all canes at the base before growth begins in spring. Fruit will be produced on primocanes in the late summer or fall. Primocanes should be soft-tipped (remove about 2 inches) when they reach 3 feet in height. Continue the soft-tipping process throughout the growing season as new primocanes emerge from the ground. In the western US, growers have found that yields increase when canes are soft-tipped twice, once at 1.5 to 3 feet and then each branch is soft-tipped at 1.5 feet. Hard-tipping is not recommended as the wounds created by the cuts will increase the likelihood of infection by pathogens.

Primocane-fruiting blackberries can also be managed with the biennial system, with a first crop on the floricanes and a second crop on the primocanes. In that case, follow the recommendations for both primocane- and floricane-fruiting blackberries. However, during the winter, last years primocanes should be pruned to just below the height where fruit production stopped in the fall. Fruit will be produced on the lower parts of the cane in the subsequent summer. In the spring and summer, soft-tip the new flush of primocanes as described above. Remove floricanes by hand after harvesting the fruit.

Floricane-Fruiting Raspberries

The biennial system is the most common training and pruning system in the eastern United States for summer fruiting raspberries. In this system, primocanes are allowed to grow throughout the season. In most cases, floricanes that produced fruit are removed immediately after fruiting to increase air movement and decrease disease pressure in the canopy. However, in colder regions of the South, these canes may serve as a source of stored carbohydrates for cold protection in the winter. Growers in the mountain regions may want to consider pruning out floricanes after the coldest part of the winter is over. In early spring, top remaining canes to a convenient picking height (usually 3 to 4 feet). If canes are too dense, fruit size will be reduced. If canes are thinned too much, total yield will suffer. In early spring, remove weaker canes and thin the remaining canes to three to four canes per square foot. Leave only the most vigorous canes, those having good height, large diameter, numerous nodes in the fruiting zone, and no obvious signs of disease, insect damage, or winter injury.

Primocane-Fruiting Raspberries

During the late winter or early spring, remove all canes at the base before growth begins in spring. Primocanes will produce fruit in the fall. To produce a late-season crop at lower elevations, cut the canes to the ground in the early spring before growth begins. When they are approximately 1 foot tall, prune the canes to near ground level a second time. Pruning in this manner will help delay harvest until late summer after the heat of the summer has passed.

Authors:

Extension Specialist (Small Fruits)
Horticultural Science
Professor
University of Arkansas
Professor
University of Tennessee

Publication date: Nov. 2, 2015
Last updated: May 12, 2017
AG-697

North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, veteran status or disability. In addition, the two Universities welcome all persons without regard to sexual orientation.