When and How to Prune Blackberry Plants

Blackberry pruning follows the plant's two-year cane cycle: canes grow in their first year (primocanes) without flowering, then flower and fruit in their second year (floricanes), and die naturally after fruiting. Managing this cycle through deliberate pruning — removing spent floricanes and managing primocane numbers — is the basis of productive blackberry growing. There are two main pruning operations, each at a different time of year.

Pruning operation 1: removing old canes after harvest (August–October)

Immediately after the last harvest of the season, cut all the canes that have produced fruit this year back to ground level. These are the floricanes — they are now dead or dying and will contribute nothing further. Cut cleanly with sharp, sterile secateurs. Remove all cut cane material from the growing area. Do not compost it if it shows any sign of disease — bag it for disposal or burn it. This operation, done promptly and thoroughly, removes the main source of fungal disease inoculum for the following season.

Pruning operation 2: cane selection in summer (June–July)

New primocanes emerge from late spring onward. A vigorous plant may produce 15 or more new canes — more than needed and more than the root system can feed well. In June or July, select the 6 to 8 strongest, most upright primocanes for retention and remove all others by cutting them at the base. Tie the retained canes in to the support structure as they grow. This summer thinning significantly improves the quality and vigour of the remaining canes.

Spring tip pruning (February–March)

In late winter, tip-prune the retained new canes by cutting back the growing tip by 15–20 cm to just above a strong bud. This prevents the cane producing an unmanageable length and directs energy into the lateral shoots that carry the fruit. On long-caned varieties, the cane length after tipping should be between 1.5 and 2.5 m — enough to carry a heavy load of fruiting laterals.