Preparing to prune

Erica Pate

Pruning blueberries is an important, time-consuming annual task for blueberry growers. While every grower has different strategies and techniques for pruning, there are a few tips that are important to keep in mind before heading out with your loppers and pruners.

Year 1-2

The goal of pruning new plantings is to establish a healthy, vigorous bush. There should be no fruit production in the first couple of years to allow the bush to establish quickly. Leaving fruit on young bushes takes energy away from the plant growth, and delays establishment.

1) Remove flower buds, the large, thick buds at the tips of laterals. Rub buds off or prune entire shoot tips.

2) Remove dead canes or weak, spindly growth.

Year 3

1) Goal is still to establish the bush and encourage vegetative growth

2) Only allow fruiting on strong shoots

3) Remove all fruit buds on weak plants

Mature plantings

In 2022, strawberry anthracnose monitoring was conducted from May 24th to September 13th. The first air sample detection of anthracnose occurred within the sampling period May 24th to 27th. Over the course of the season, 84 samples were collected from the three different sites. A total of 51 positive results were found throughout the season and each site had positive results. Spornado samplers were able to identify anthracnose, and may be a tool for growers to time fungicide applications. Using these samplers can also provide

As plantings mature and are encouraged to produce larger yields, the goal of pruning shifts to maintaining a balance of vegetative growth and fruit production (Figure 1). Most berries are produced on one-year-old laterals on young canes (2-5 years); these young canes are more efficient producers and produce the best fruit. With regular pruning, older, unproductive wood is removed and replaced with younger, productive cane. New canes should be produced every year. It’s important to maintain a balance of fruit production and new shoots which produce next year’s crop. Pruning also helps manage bush height and shape and removes dead and diseased canes. Pruning and opening up the canopy improves harvest efficiency, and is also beneficial for pest management, including spotted wing drosophila control.

Tips for pruning blueberries:

1) Prune every year

2) Prune out weak, spindly, diseased and dead canes

3) Prune out canes older than six years. These canes are thick with gray, peeling bark (Figure 2).

General recommendations are to prune one of every six canes.

4) Thin remaining canes, leaving most growers a quick method of determining presence of resistance on their farm, and helping growers choose which products to use. Fast and reliable information on the presence of disease and fungicide resistance can help growers make better, more effective fungicide applications. Following the results of this project there are opportunities to expand monitoring to include other pathogens in strawberries, such as powdery mildew, and expand fungicide resistance tests. Spornado has developed tests tests for a number of crop/disease combinations, including early and late blight in potato and tomato, Botrytis in pepper, apple scab and downy and powdery mildews in grape.

A final report summarizing all results, including the fungicide resistance testing, will be available in spring 2023. If you would like a copy of the report or more information, please contact info@spornadosampler.com vigorous canes.

5) Cut canes as low as possible.

6) Detail pruning: Remove twiggy growth (unproductive laterals). Berries are produced on one-year-old laterals, and thicker laterals produce bigger berries. Twiggy canes with a lot of weak, small laterals are unproductive.

7) Weaker plants with little vegetative growth need to be heavily pruned to regain the balance of vegetative growth and fruit production.

8) The best time to prune is when plants are fully dormant. Pruning in the fall may stimulate late growth and lead to winter injury on canes that don’t harden off.