Pruning Brambles
Unlike other perennial fruiting plants, raspberries and blackberries are unique and require special pruning to be productive. While the plants themselves are perennials, the canes they produce are typically biennials meaning they grow one year, produce fruit the next and then die. Because of this they are unique in their pruning requirements. To make things even more complicated it’s important to know the variety you have because some berries are everbearing and need to be pruned differently. Let’s take a look at each option.
Black or purple raspberries and thornless blackberries.
These fruiting bushes tend to grow in a clump and it’s best to remove all but five to seven of the largest and healthiest canes in the clump for the best harvest. Prune out any dead canes at this time as well. Remove any winter damage from the remaining canes. For black raspberries you should also prune the canes back so only 8-10 buds per cane are left while purple raspberries and thornless blackberries are more vigorous growers and you should leave more buds per cane for best harvest. Thornless black berries might produce some suckers a short distance from the main clump that can be dug up to increase the size of the planting.
Red raspberries and thorny blackberries
These bushes tend to sucker badly and will fill the row with new plants. For these plants remove any dead canes, prune the small canes back so you leave the largest canes spaced approximately 4-6” apart then prune those canes back to five feet. Keep the aisles between rows clean by mowing any new suckers that sprout off or cutting them back to the ground.
Everbearing red raspberries and blackberries
These plants are the exception in that they will fruit on first year canes. For these varieties cut all the canes off to the ground in the winter for the best result. Since these varieties fruit best on first year canes you will still get a vigorous yield of berries.
