When Do I Prune Blackberry Plants?

Pruning in the First Year

• Blackberries don't need pruning in their first year unless the canes become insect-infested or damaged. In that case, cut back the damaged canes to the base of the bush, but leave the rest of the plant intact.

Diseased Blackberry Canes

• Blackberry diseases are difficult to remedy and are very contagious. Once a cane becomes diseased, it's best to prune the entire bush down to soil level. Burn the diseased canes away from the blackberry bed, or take them to a community compost site. Don't use any part of the diseased plant in your compost pile.

Pruning Primocanes

• Primocanes are first-year canes. Next year's crop of berries will form on these canes. Prune the top 1 inch of the primocanes when they reach 30 to 36 inches tall. After the canes have gone dormant in the late fall or early winter, thin the primocanes by cutting all but the five largest canes down to the base of the plant. Trim the side branches (called laterals) of the remaining primocanes to a length of 12 to 18 inches.

Pruning Floricanes

• When canes are in their second year of growth, they are called floricanes. Cut floricanes back to the base of the bush after they have finished bearing fruit for the season.

Pruning for Control

• Prune your blackberries at any time of the year to remove canes that are encroaching on your lawn. If your blackberry bush is trained to a trellis, prune canes that grow too tall or in the wrong direction to be tied to the supports. If primocanes grow so tall that they interfere with the harvest of the current year's crop, or crowd the bearing canes, prune them to below the height of the floricanes.