Cultivated blackberries fruit on canes that grew the previous year. That makes pruning straightforward: once a cane has fruited, cut it out, and tie in the new growth that will crop next summer. Do it every year and the plant stays productive and easy to pick.
How blackberries fruit
Blackberries produce new canes each summer. Those canes overwinter, fruit the following summer, and are then finished. Knowing which cane is which is the whole trick: the old, fruited canes are darker and woodier, and the new ones are greener and more flexible.
Step by step
- After harvest, cut every cane that has fruited down to the ground.
- Choose the strongest new canes, roughly five to eight per plant, and remove weak or damaged ones.
- Tie the chosen canes in along your wires, spacing them out so light and air can reach them.
- Trim any overlong tips if they extend past the top of the support.
Training keeps things tidy
A common method is to fan the fruiting canes out along the wires on one side and train the new canes on the other, so the two never tangle. The fruit is then easy to reach, and there is no need to guess which cane is which next winter.
Thornless varieties
Thornless blackberries are pruned exactly the same way, and they make the job far less painful. My guide to growing thornless blackberries covers varieties and planting.
If you also forage, see my complete guide to foraging blackberries. Pruning cultivated canes is a different job from anything you would do to a wild bramble.
Common mistakes
Cutting out the new canes. The green, flexible canes that grew this year are next summer's fruit. Only remove the ones that have already fruited, or that are weak or damaged.
Leaving every cane. A mass of tangled canes shades the fruit and encourages disease. Choosing the strongest and removing the rest gives better, easier-to-pick fruit.
Tying in too tightly. Canes thicken as they grow, so use soft ties with a little room to expand.
Tools and safety
Wear thick gloves and long sleeves, and use long-handled loppers so you can cut from a safe distance. Bag or compost the old canes promptly, as cut stems can be very prickly to handle. Thornless varieties make this job far more pleasant.
Frequently Asked Questions
When should I prune blackberries?
After fruiting, from autumn into winter. Cut out the canes that have fruited and tie in the new ones.
Do thornless blackberries need pruning differently?
No. They are pruned and trained in the same way as thorny types.
How many new canes should I keep?
Roughly five to eight of the strongest new canes per plant is a good guide, spaced along the wires.
