Blueberry Bushes: Pruning and Fertilizer

Credit: iStock / Kativ

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Q: How and when do you prune blueberry bushes? What type of fertilizer is used, and how often and when should I use it?

“Blueberry” (Vaccinium spp.) can be pruned during dormant period (November to late February) when stems are bare to allow one to see fruiting buds (fatter in size) compared to growth/leaf buds.

The main objective is to open up the centre of the bush to allow more light or air movement, with stems ranging in age from one to four years old. The first two years, remove weak growth and strip off flower buds, both or which encourage more upright stems. When plants are in early years of production remove low, weak and horizontal growth.

On established plants, thin out unproductive (very old and weak) stems to ground level. Remove any low growth which might end up on the ground when loaded with fruit. Cut back weak growth to a strong side shoot on remaining stems.

No fertilizing is required during the first season. The following spring apply a split application of berry fertilizer as directed on the package. Suphate of ammonia (21-0-0) could also be used especially on mineral soils. Rates can start at 20 to 40 grams to a maximum of 400 grams per plant. Be careful with fertilizers, as it can burn, so spread evenly, keeping away from the base of blueberry by about 10 centimetre beyond the drip line.

Never fertilize when soil is dry. Apply compost mulch as needed but not touching the stems.