Winter Care for Blueberry Bushes

Blueberry varietals are hardy in USDA zones 2 through 8 and vary somewhat in their performance in cold winter temperatures and how well they weather winter conditions. Most new blueberry growth with be damaged or killed at temperatures below 28 degrees Fahrenheit, so discouraging fall growth that won't have time to acclimate and harden off is a key step in winter care. Along with protecting the roots with mulch, wrapping the bushes, watering deeply and applying pre-emergent insecticides your blueberries will come into spring as healthy plants.

Most young blueberry growth with be damaged or killed at temperatures below 28 degrees Fahrenheit. They also require at least 850 hours of progressively colder temperatures to acclimate and become cold hardy. By discouraging growth that won't have the time to acclimate and harden off before temperatures drop, you take your first important step in helping the blueberries to safely survive the winter. To prevent growth late in the season, stop fertilizing by the late summer. Wait to conduct pruning until after the blueberry shrub goes dormant to prevent new growth from forming. Conduct annual pruning of the canes during the later part of winter or in the early part of spring.

Keep the soil around the blueberries moist to prevent drought stress in their dormant months by watering deeply before the first heavy frost. The roots are less cold hardy than other woody parts of the blueberry shrubs, so mulching around the root ball to beyond the drip line of the blueberries will help protect them from cold damage. You can mulch with the traditional blueberry mulch of sawdust or you can use shredded bark or pine needles in lieu of the sawdust. In very windy and cold winter conditions, create windbreaks or wrap the sides of the blueberry bushes in burlap or other material to lessen the freezing impact of the winds.

As you see them, cut away diseased or damaged canes with clean sharp secateurs throughout the fall and winter to prevent any spreading or invitation of disease over the months of winter stress. Apply herbicides and insecticides after dormancy comes in late November and December; for instance, spray for scale and copper spray for bacterial canker to ensure healthy plants in the spring.