American red raspberries need pruning several times throughout the growing season to remain productive and healthy. Prune red, black, gold and purple American raspberries to grow large berries and large yields.
In early spring, groom the width of the row so that it stays between 12 and 18 inches wide. Drive a spade into the soil and sever the roots of any plants that fall outside of this width. Remove and throw away the excess roots.
Cut the tips of new growth in late June or when new 1-year-old canes reach 30 inches high. Lateral branches will grow from these canes.
After the 2-year-old fruiting canes have finished producing fruit, remove them. These fruiting canes die soon after the harvest and should be removed. Cut them off an inch above ground level.
Cut back lateral branches in late summer so each lateral is left with 2 to 6 buds. Lateral branches grow from new 1-year-old canes and will produce fruit the following year.
Thin each American red raspberry in late summer. Thin out all new canes, leaving at least four canes for each foot of planting row.
Prune out canes under ½ inch diameter in late winter. Leave between two and five healthy canes on each plant.