Pruning Guide for Vaccinium corymbosum (Highbush Blueberry) & Vaccinium angustifolium (Lowbush Blueberry)

Vaccinium corymbosum, highbush blueberry, and Vaccinium angustifolium, lowbush blueberry, are popular deciduous shrubs cultivated for their delicious berries. Highbush blueberries grow up to 6-12 feet tall, while lowbush varieties stay more compact, usually between 1-2 feet tall. Proper pruning is essential for maintaining these plants' health, productivity, and shape, encouraging vigorous growth and abundant berry production. Without regular pruning, these bushes can become tangled, less productive, and susceptible to disease.

Pruning Objectives

The main goals when pruning highbush and lowbush blueberries are:

• Promoting Health: Removing dead, damaged, or diseased wood helps prevent pests and disease spread.

• Shaping the Plant: Ensure an open structure to help with air circulation, sunlight penetration, and overall bush shape.

• Encouraging Fruiting: Removing old wood promotes new, vigorous growth, which bears more fruit.

• Size Control: Keeping the bush within a manageable size makes harvesting easier and keeps the plant healthy.

Pruning Season and Timing

The optimal time to prune blueberries is late winter to early spring, just before the onset of new growth but after the worst of winter has passed. This timing allows you to identify and remove winter-damaged branches and stimulates new growth. Avoid pruning in late fall, as this can stimulate tender new shoots vulnerable to winter damage. Lowbush blueberries can also be pruned back hard (even mowing them) every two to three years to rejuvenate growth and improve yields.

Pruning Techniques

• Remove Dead, Damaged, and Diseased Wood: Remove any dead, damaged, or diseased branches. This helps maintain plant health and prevent disease.

• Thin Out Older Canes: Blueberry bushes produce the best fruit on canes 2-4 years old. Each year, remove 1-2 of the oldest canes (grey and woody) at the base to encourage new growth.

• Open the Center: Prune to create an open structure in the middle of the plant. This allows sunlight to reach the interior branches, improving fruit production and reducing fungal diseases.

• Shape the Plant: After pruning, highbush blueberries should have 6-8 main canes of varying ages. Focus on creating a balanced, vase-like shape. For lowbush varieties, mow or prune back every few years to the ground to promote new growth.

Common Pruning Mistakes and Tips

• Over-pruning: Removing too much at once can stress the plant. Limit removal to about 20-25% of the plant's annual growth.

• Ignoring Old Wood: Failing to remove old, non-productive canes can lead to reduced berry production.

• Pruning at the Wrong Time: Pruning too late in the spring can remove developing flower buds, reducing fruit yield. Always aim to prune before new growth begins.

• Not Opening the Plant: Dense growth can limit airflow, increasing disease risk. Always focus on opening the center.

Special Considerations

• Highbush Blueberries: Highbush blueberries benefit from annual pruning to maintain productivity. They should maintain a vase-like shape with 6-8 main canes of varying ages. Prune to encourage light penetration and airflow and remove old and unproductive wood.

• Lowbush Blueberries: Lowbush blueberries can be cut back hard every 2-3 years. They often require less detailed pruning compared to highbush varieties. Pruning lowbush varieties may involve mowing or cutting them back to ground level, encouraging dense new growth and increasing yields.

Benefits of Proper Pruning

• Increased Yield: Pruning encourages the growth of new, productive shoots, which are more likely to produce abundant fruit. By selectively removing old and non-productive canes, energy is redirected to newer, more vigorous growth, resulting in higher yields.

• Healthier Growth: Removing dead or diseased branches prevents disease spread and allows the plant to focus its energy on new, healthy growth. Pruning helps remove any weak or damaged parts that could otherwise invite pests or harbor pathogens, improving the plant's resilience and overall vigor.

• Improved Plant Structure: A well-shaped plant receives better air circulation and sunlight, which reduces disease risk and improves berry quality. By opening up the center and maintaining a balanced structure, the plant can more effectively allocate its resources, leading to more vigorous canes and better overall health. Proper structure also makes harvesting more accessible and more efficient, allowing light to penetrate throughout the plant and ensuring that berries develop uniformly.

Maintenance After Pruning

After pruning, provide proper care to encourage healthy new growth:

• Fertilization: Apply a balanced, acid-loving plant fertilizer in early spring to support new growth.

• Watering: Ensure the plant is well-watered, especially during dry spells. Blueberries have shallow roots, so consistent moisture is vital.

• Mulching: Apply a 2-4 inch (5-10 cm) layer of mulch around the base of the plant to retain moisture, reduce weeds, and protect the shallow root system. Pine needles or bark mulch are good options for blueberries.

Proper pruning, combined with thoughtful aftercare, can result in healthy plants with greater yields year after year.

Variety Name	Type	Fruiting Time	Hardiness Zone
Bluecrop	Highbush	Late Season	4-7
Jersey	Highbush	Late Season	4-7
Duke	Highbush	Early Season	4-7
Patriot	Highbush	Early-Mid Season	3-7
Northblue	Half-High	Mid Season	3-7
Chippewa	Half-High	Mid Season	3-7
Blueray	Highbush	Mid Season	4-7
Reka	Highbush	Early-Mid Season	5-7
Burgundy	Lowbush	Mid Season	2-6
Top Hat	Lowbush	Mid-Late Season	3-7
Polaris	Half-High	Early Season	3-7
Wild Lowbush	Lowbush	Late Season	2-6