Winter preparation for boysenberry bushes

Boysenberries, a hybrid of blackberries, raspberries, loganberries, and dewberries, require specific care to survive winter, particularly in USDA Hardiness Zones 4 through 7. While the roots are perennial, the above-ground canes are vulnerable to extreme cold.

To prepare for dormancy, gardeners should prune the plants before the first frost. This involves keeping five to seven healthy primocanes per plant, shortening laterals to approximately twelve inches, and removing spent floricanes to prevent disease.

Insulation is critical for survival in colder regions. Applying at least eight inches of straw mulch around the root and cane area provides lightweight protection. In extremely cold zones, growers may bend dormant primocanes to the ground, cover them lightly with soil, and then pile straw on top to moderate moisture and temperature.