Hazelnut Trees: How to Plant, Prune, and Harvest

Choosing the Right Hazelnut Variety

Selecting the right variety is the foundation of hazelnut growing. European hazelnuts (Corylus avellana) dominate commercial production worldwide, with popular cultivars like Barcelona, Jefferson, and Ennis offering large nuts, thin shells, and high yields. However, they are more vulnerable to Eastern Filbert Blight (EFB), a serious fungal disease. American hazelnuts (Corylus americana), native to North America, produce smaller nuts but are highly disease-resistant and can withstand harsher winters. Modern hybrids such as Yamhill, Eta, and Gamma combine the large nut size of European varieties with the resilience of American types, making them ideal for areas prone to EFB or extreme cold.

Site Selection and Preparation

Hazelnuts thrive in full sun and well-drained soils with a pH between 6.0 and 7.5. They prefer loamy soils but will tolerate sandy or clay conditions if drainage is adequate. Avoid low-lying areas where cold air and excess moisture can accumulate, as these conditions encourage disease. For commercial orchards, conduct soil testing months before planting and amend with lime or organic matter as needed. In backyard settings, preparing the site by removing weeds, loosening the soil, and adding compost ensures strong early growth.

Planting for a Productive Orchard

Hazelnuts can be planted in early spring or late fall when the trees are dormant. Space European varieties about 15–20 feet apart and American or hybrid varieties 10–15 feet apart. They are wind-pollinated and require cross-pollination between two compatible varieties for good nut set, so plant at least two different cultivars within 50 feet of each other. Dig a hole wide enough to spread out the roots, planting at the same depth they were in the nursery. Water thoroughly to settle the soil, and apply mulch to retain moisture and suppress weeds, keeping it a few inches away from the trunk to prevent rot.

Early Care and Establishment

The first three years are critical for establishing a strong root system and healthy framework. Hazelnuts benefit from regular watering, especially during dry spells, but avoid waterlogging. Fertilize lightly in early spring with a balanced fertilizer based on soil test results. Remove any suckers (new shoots emerging from the base) during the growing season to direct energy into the main stems. Keep the area around young trees weed-free to reduce competition for nutrients and moisture.

Pruning for Structure and Longevity

Hazelnuts can be trained as a multi-stemmed bush or a single-trunk tree. In commercial systems, the bush form is common, allowing for easier harvest and sucker replacement, while single-trunk forms are more ornamental for backyard landscapes. Pruning should focus on removing dead, diseased, or crossing branches and thinning the center to improve airflow and sunlight penetration. Conduct major pruning in late winter while the trees are dormant. For bush-form trees, maintain 4–6 strong stems, replacing older stems with vigorous suckers every few years to keep the plant productive.

Managing Pollination

Since hazelnuts are wind-pollinated, ensuring good pollination is crucial. Male catkins release pollen in late winter to early spring before the leaves emerge, while tiny red female flowers bloom on separate buds. Timing between pollen release and female flower receptivity can vary between varieties, so choosing compatible cultivars with overlapping bloom periods is essential. In commercial orchards, planting pollenizer rows or alternating cultivars increases nut yields. For backyard growers, even two or three trees of different varieties can ensure excellent pollination.

Irrigation for Nut Development

While hazelnuts are relatively drought-tolerant once established, consistent moisture during nut development—from spring through midsummer—significantly improves nut size and kernel quality. Drip irrigation or soaker hoses provide steady water without wetting the foliage, which can reduce disease pressure. Monitor soil moisture and adjust irrigation based on weather conditions, as both water stress and overwatering can affect nut fill.

Nutrition for Bigger, Better Hazelnuts

Hazelnuts benefit from balanced nutrition, especially nitrogen, which fuels leaf and shoot growth. Apply nitrogen in early spring, but avoid late-season applications that encourage tender growth susceptible to frost. Potassium and calcium are important for nut fill and shell quality, while micronutrients like boron support flower development. Regular soil and leaf tissue tests help fine-tune fertilization to your orchard’s specific needs.

Protecting Against Pests and Diseases

The most significant disease threat to hazelnuts in North America is Eastern Filbert Blight (EFB), which can kill branches and eventually entire trees. Planting resistant varieties is the most effective prevention. In non-resistant orchards, pruning infected wood during dormancy and applying fungicidal sprays at the right time can help control the spread. Other pests include filbertworm, leafrollers, and aphids. Maintaining good orchard sanitation—removing fallen nuts, leaves, and pruned material—reduces pest habitat. Beneficial insects and birds can also help keep pest populations in check.

Weed Control and Orchard Floor Management

Weeds compete with young hazelnut trees for nutrients and water, reducing growth and yield potential. Mulching with organic materials like wood chips or straw suppresses weeds and improves soil health. In commercial orchards, herbicide strips under the trees combined with mowed grass or cover crops between rows provide an effective management system. Cover crops like clover can also improve soil fertility and attract pollinators.

Harvesting Hazelnuts at Peak Quality

Hazelnuts typically ripen in late summer to early fall. The nuts develop inside leafy husks called involucres, which turn brown and open when the nuts are mature. In commercial settings, mechanical sweepers and harvesters collect fallen nuts from the orchard floor. Backyard growers can hand-pick nuts as they drop or shake branches to encourage them to fall. Harvest promptly to prevent losses to wildlife such as squirrels and jays, which are particularly fond of hazelnuts.

Post-Harvest Handling and Storage

Once harvested, remove the husks promptly to prevent mold. Dry the nuts in a single layer in a well-ventilated area for two to three weeks until the kernels reach about 10% moisture content. Properly dried hazelnuts have a crisp texture and store well for months in a cool, dry place. Refrigeration or freezing extends shelf life and preserves flavor, especially for nuts intended for roasting or confectionery use.

Maintaining Long-Term Productivity

Hazelnuts can remain productive for decades if properly maintained. Annual pruning, sucker management, and soil fertility adjustments keep trees vigorous. Replacing older stems with young suckers every few years rejuvenates growth and maintains consistent yields. In commercial orchards, periodic replanting of sections ensures a steady supply of high-quality nuts as older plants decline.

Common Mistakes to Avoid

Several common errors can reduce hazelnut yields. Planting a single variety often leads to poor pollination and low nut set. Neglecting sucker removal can result in overcrowding and reduced airflow, increasing disease risk. Overfertilizing, especially with nitrogen, can promote excessive vegetative growth at the expense of nut production. Ignoring early signs of EFB can lead to rapid orchard decline. Lastly, delaying harvest gives pests and wildlife the upper hand, reducing your yield.

The Payoff of Growing Hazelnuts

Whether grown on a few backyard trees or across a commercial orchard, hazelnuts reward growers with annual harvests of delicious, high-value nuts and the satisfaction of working with one of the world’s most versatile crops. With the right variety choice, careful planting, timely pruning, and attentive harvest practices, you can enjoy abundant, high-quality hazelnuts year after year, building both a culinary and horticultural legacy.