Tipping or tip pruning is highly recommended for black and purple raspberry canes. As the primocanes (first year canes) reach 90-120 cm (3-4'), pinch or cut 8-15 cm (3-6”) off the tips to force branches to develop. Tipping will delay, but prolong, the harvest, increase yield and reduce arching of the canes and tip rooting. Pruning later in the season decreases the amount of time the plant will have to develop the branches. Not pruning the primocanes will allow earlier ripening than the tip-pruning option, however the
canes will become tall and arching, and will develop fewer berries.