Blueberry bushes grow best in full sun, where they gather energy for fruit production. After fruit production, however, the bush begins to decline and go dormant for winter. In the first few years, you must help the bush with this task so it does so properly and safely. Otherwise, serious winter injury could occur that may even kill the plant.
Stop fertilizing after the blooming period. The excess nitrogen will produce new growth on the bush. New growth is particularly susceptible to winter dieback, which then opens up the plant to disease.
Water the plant 1 to 3 inches a week into the fall. This will provide enough moisture for the winter. Stop watering at the end of harvest so the blueberry bushes can go dormant.
Place a 3- to 4-inch layer of straw mulch around the base of the blueberry bushes. This will protect the shallow, fibrous root system from extreme temperature fluctuations and frost.
Prune the blueberry bushes in late winter--sometime between January and March--when the bushes are dormant. Cut out dead and diseased branches with pruning shears, as well as weak, spindly growth. Remove the oldest unproductive canes to increase air flow through the bush.