To maximize yields, raspberries must be pruned in spring and summer. Pruning increases crop yields and helps control diseases. The pruning procedures for red, black, and purple raspberries (based on the growth and fruiting characteristics of the plants) are outlined below.
Summer-Bearing Red Raspberries
After the last harvest, prune off the old fruiting canes at the soil surface. Remove the pruned canes from the garden and destroy them.
Fall-Bearing Red Raspberries - Two Crop System
After harvesting the summer crop, remove and destroy the old fruiting canes. (Do not prune the new canes as they will bear a crop in late summer/early fall at the shoot tips.)
Fall-Bearing Red Raspberries - One Crop System
No summer pruning is necessary.
Black and Purple Raspberries
Pinch out or cut off the shoot tips when the new canes reach a height of 36 to 48 inches. Remove the top 3 to 4 inches of the shoots. Pinching encourages lateral shoot development and increases the fruiting surface area, resulting in higher yields. Because all new shoots will not reach the desired height at the same time, it will be necessary to go over the planting approximately once each week between late May and late July. Discontinue shoot tip removal at the end of July. Canes that develop after July are small, weak, and unproductive; prune them out the following spring.
After the last summer harvest, remove the old fruiting canes at the soil surface and destroy them.