Bramble fruits, including both blackberries and raspberries, have a biennial cane life cycle, meaning each cane lives for two years. New shoots emerging from the perennial root system in the first year are called primocanes. These primocanes become floricanes in their second year, which flower, produce fruit, and then naturally die. Pruning manages this two-year cycle, directing the plant’s energy toward developing strong new canes and maximizing the harvest on fruiting canes.
Pruning Timing for Blackberries
The primary pruning event for floricane-fruiting blackberries, which includes most traditional varieties, occurs immediately after the summer harvest, usually in mid-to-late summer. All spent floricanes must be cut down to the soil level. These canes will not fruit again and should be removed quickly to prevent disease and redirect resources to the new primocanes that will bear fruit next year.
Summer pruning also involves managing new primocanes, especially for erect blackberry varieties. When these first-year canes reach 36 to 48 inches, their tips should be pinched or cut off in late June or July. This practice, known as tipping, encourages the cane to stop vertical growth and produce lateral branches. This significantly increases the potential fruiting surface area for the following season. Trailing and semi-erect varieties are not typically tipped, but their long primocanes should be guided and tied to a trellis throughout the growing season.
Pruning Timing for Raspberries
Pruning schedules for raspberries depend on whether the variety is summer-bearing or fall-bearing (everbearing). Summer-bearing raspberries fruit on second-year floricanes and are pruned like blackberries: all spent floricanes are removed immediately after the mid-summer harvest. This post-harvest removal opens the canopy for new primocanes and reduces disease risk.
Fall-bearing or everbearing raspberries offer two distinct pruning options, allowing growers to choose between one or two crops per year. For a single, larger fall harvest, all canes are cut down to the ground in late winter or early spring, before new growth begins. This method simplifies the process by forcing the plant to produce fruit only on new primocanes in the late summer and fall.
The second option is managing the plant for a double crop, yielding a small summer crop and a fall crop. This involves removing only the upper portion of the cane that fruited in the fall, leaving the bottom part intact to overwinter. This lower portion, now a floricane, produces an early summer crop the following year before it is removed completely after fruiting. This approach increases labor and may not result in a greater total yield than the single fall crop method.
Dormant Season Pruning for Both Cane Types
Dormant season pruning should be carried out in late winter or early spring, just before new growth starts. This timing allows for the removal of canes damaged by winter cold or disease. The primary task during this period is thinning the remaining healthy canes to ensure proper air circulation and light penetration.
Thinning involves removing the smaller, weaker canes at the base, leaving only the strongest, most vigorous canes. A goal is to leave four to eight canes per foot of row, depending on the variety’s vigor. This structural thinning prevents overcrowding and contributes to better fruit quality and plant health.
The second major dormant task is height reduction, particularly for floricane-fruiting varieties and overwintered primocanes. Canes taller than five to six feet are cut back to that height, which encourages the development of strong lateral branches in the spring. Additionally, the lateral branches on floricanes should be shortened to 12 to 18 inches to promote larger fruit size and manage the plant’s width.