Blackberries are a biennial fruiting plant, meaning they produce fruit on second-year-old canes. Regular pruning will increase fruit production and prevent conditions that cause disease. Pruning the upright new growth tips of blackberry canes in the spring season promotes branching growth for increased fruit production for the following fruiting season. The current year fruiting canes should not be pruned until the fruiting season is complete.
Thin the canes in early spring by cutting two-year-old blackberry canes at the ground level so there are five to seven canes remaining on each plant.
Remove all dead and weak canes and branches once the spring growth starts by cutting them to ground level. Removing these dead and damaged canes in spring will promote new growth.
Prune the tips of current-year blackberry cane growth in the spring by removing growth so a length of 24 to 30 inches remains. Do not remove the tips on second-year growth, as these are the fruit-producing canes. This process is called tipping.
Prune current-year cane growth that is shorter than 24 inches by cutting 1 inch off the tips of the cane. Prune the tips of the previous-year lateral shoot growth each spring to a length of 18 inches. This will prevent winter injury of the canes.