Blueberries, like most fruiting shrubs and vines, benefit from annual pruning to thin dying canes, train the plant into a healthy growth form and promote more abundant fruit harvests. Because blueberry bushes are vigorous growers, pruning for size and shape in smaller gardens also allows for easier access to the fruit during harvest.
Annual Seasonal Pruning
Prune both high-bush and low-bush wild blueberry plants each year during their dormant period in the late fall or winter. During the winter, you can clearly see the flower/fruit buds along last year's canes to guide your pruning cuts, which will determine the fruit harvest in the coming season.
Blueberry bush canes and wood can vary greatly in diameter, so you may need a few tools to complete the job. Arm yourself with secateurs for smaller canes near you, long-handled loppers to reach up and into the plant and a hand or pole saw to remove the oldest, largest wood from the bush.
Your goal is to make clean, crisp cuts without pulling away any cambium from the cut site or nicking productive canes. Always make sure that your cutting blades are clean to prevent the introduction of disease. Wipe the blades with a 10-percent household bleach and water solution or with undiluted isopropyl alcohol before and after your pruning session as a preventive measure.
Give your blueberry a visual once-over, looking for damaged, diseased or dying canes. Cut those away first, pulling the cut canes from the bush and disposing of them in a waste bin, not a compost pile. Prune annually to achieve and maintain an overall shape to the bush. The top should be wide and open to the sunlight and air, tapering down as you move toward the main trunk.
Each year cut away two or three of the oldest, grey canes spaced throughout the bush. These will be seven years or older with a larger diameter. Next, prune away canes that cross or abrade one another or are tangled, creating vegetative clutter in the plant structure. On young blueberry bushes of a few years, prune lightly, only to create a healthy open-branching structure. Next make perimeter cuts for height and spread if needed to suit the space. To maximise fruit-producing canes on mature blueberries for the next season, limit cuts on canes where buds are visible.