Pruning Erect Blackberries in the Home Garden

Blackberries can make a nice addition to the home fruit garden as a beautiful living hedge with nice flowers and tasty fruits. Gardeners can also enjoy blackberries as fresh fruit, jam or cobbler. Maintaining a neat, clean blackberry planting can be a considerable challenge. A good weed, fertility and pest control program can promote plant growth and quality fruit. Annual pruning of blackberry plants is also essential for high quality fruit production.   

	Figure 1. Thornless blackberry bushes loaded with fruits. Photo by Gary Gao, OSU South Centers.

Proper establishment of blackberry plants is important. This fact sheet is intended to help gardeners better understand how blackberries should be pruned. Refer to the glossary of terms if you are not familiar with some of the words used in this fact sheet. Thorny, erect blackberries tend to be more aggressive in their vegetative growth than thornless varieties. Thornless, erect varieties tend to be slower to fill in rows and overall are more manageable than thorny blackberries. Blackberry vegetation can be managed through effective pruning practices and still maintain good quality fruit production.

When is the Best Time to Prune Blackberry Plants?

Since blackberry plants are not as cold hardy as our fruit crops, it is beneficial to conduct dormant pruning as late as possible. Late March or early April may be typical timing for most parts of Ohio. Floricane bearing cultivars can lose many canes to winter injuries. It is a good idea to wait until the full scope of winter injuries can be assessed.  

Primocane-fruiting blackberries (e.g., Prime Jim, Prime Jan) bear fruit on new canes that grew during the summer. This is different than floricane production in which the fruit is produced on canes that grew the previous year. Once fruiting is completed and frost has occurred, all primocanes can be pruned or mowed off. An alternative approach is to remove canes in early spring prior to when new growth emerges in March. Refer to the follow sections for more detail.          

Why is it Important to Prune Blackberries?  

Blackberries can become unmanageable if not pruned each year (Figure 2). Pruning can help you to maintain a fairly tangle-free blackberry patch and hopefully it will be a more enjoyable area in which to pick fruit (Figure 3). It is also important to keep the erect blackberries in a confined space in the garden. If allowed to do so, blackberries will send up new shoots out in other areas of the garden and yard.

Figure 2. Primocanes of thorny, erect blackberries that have not been pruned.	Figure 3. Primocanes of thorny, erect blackberries that have been pruned.

What Steps Should be Followed to Successfully Prune Floricane-Fruiting Erect Blackberries?

Blackberries are considered to be biennial fruiting plants. Primocanes are actively growing vegetative shoots that are produced in the first year, and the floricanes are normally the fruit-producing canes. Some erect blackberry varieties (e.g., Prime Jim, Prime Jan) produce fruit on primocanes in the fall. Primocanes, left untipped, can grow several feet in length. In the following year, primocanes mature into floricanes. Once the fruit has been harvested, the floricanes will eventually die. All spent floricanes should be removed from the blackberry planting. By removing the spent floricanes, more room will be available for new primocanes to grow the following year. 

The following steps will help you to keep your blackberry planting in good condition.

1. Take time to observe the planting and determine what canes need to be pruned.
2. During the growing season, tip back each developing primocane to 48 inches in late June and July.
3. Lateral shoots will develop throughout the growing season.
4. Tip lateral shoots back to 18 inches in the spring of the following year to avoid winter injury.
5. Do not prune floricanes before the fruiting season unless damaged or diseased.
6. When the fruiting season is over, use loppers to cut out spent floricanes at the root crown.
7. Discard all pruned plant material.

Are There Different Pruning Systems for Thorny and Thornless Varieties?

Thorny and thornless erect blackberries are generally pruned in the same manner. The thorny canes are more challenging to handle and often gardeners wear gloves and long-sleeved shirts to provide protection. Thornless varieties are smooth to the touch and are fairly easy to handle. Thorny blackberries tend to produce more canes and have more vegetation than thornless. Both thorny and thornless blackberry plants can bear green leaves well after frost.

How Should Blackberries Be Tipped to Maximize Fruit Production?

As each new cane reaches approximately 4 to 5 feet, they should be tipped back (Figure 4). By tipping the ends of the canes, apical dominance is removed and growth hormones in the canes are released. This process will stimulate new growth from the lateral buds. Lateral shoot growth that develops prior to fruit bud formation will increase the amount of plant surface area in which fruit can be produced. With more aggressive varieties it is possible that the lateral branches will need to be tipped as well to help restrict the overall plant growth.

What Tools are Used for Pruning?

Figure 4. Blackberry canes tipped during the growing season tend to produce laterals which will bear fruit in the following season. Photo by Ryan Slaughter, OSU South Centers.

Hand tools such as loppers and hand pruners can be used to effectively remove spent canes from the blackberry planting. Select the appropriate tool to cleanly remove old canes. Hand pruners can be used to effectively remove tips of actively growing canes. Loppers are generally the tool of choice when removing several canes. Be sure that all pruning tools are maintained properly. Sharp tools will enable you to make smooth cuts and will cause less stress on the plants. 

Summary

Learning to master the art and science of pruning blackberries takes time and practice. Contact your county Extension educator for updated information on pruning. Make sure your blackberries are pruned each year to maintain the size and shape of the planting, maximize fruit production, and increase the overall fruit quality. Gardeners are also encouraged to purchase a copy of the OSU Extension Bulletin, 940, Midwest Home Fruit Production Guide, for additional information.

Glossary of Pruning Terms

• Floricane: This is normally considered to be the fruit-producing cane and was a primocane in the previous growing season.
• Lateral shoot: The leafy, green growth that develops from the lateral buds. Lateral shoots grow quite rapidly when the main shoot (cane) is tipped.
• Node: The thickened portion of a shoot (cane) where the leaf petiole is attached and a bud is located.
• Primocane: Blackberry plants have a biennial growth habit. The first-year growth is a green shoot that matures into a woody-textured cane late in the fall.
• Primocane fruiting: Some blackberry varieties are genetically able to produce fruit on primocanes in the fall.
• Pruning: Remove portions of blackberry plants to help maintain size, shape and productivity.

References

• Funt, R., M. Ellis, R. Williams, D. Doohan, J. Scheerens, and C. Welty. 1999. Ohio State University Extension Bulletin 782, Brambles Production Management and Marketing. Columbus, OH: The Ohio State University.
• Gao, G., R. Becker, M. Brown, M. Ellis, S. Prochaska, C. Welty, and R. Williams. 2017. Ohio State University Extension Bulletin 940, Midwest Home Fruit Production Guide. Columbus, OH: The Ohio State University.