Hazelnut trees belong to the genus Corylus, which is part of the birch family, Betulaceae. The genus includes both shrubs and small trees, and about 15 recognized species exist globally. These plants are deciduous and typically grow in temperate regions, known for their characteristic rounded, serrated leaves, drooping catkins, and edible nuts. Hazelnuts are also commonly referred to as filberts in some regions, particularly in Europe.
The history of hazelnut trees stretches back thousands of years. Archaeological evidence suggests that humans have gathered wild hazelnuts since the Mesolithic period. Over time, especially in Europe and western Asia, these trees were domesticated and selectively bred for larger nuts and better yields. Ancient Greeks and Romans valued hazelnuts not only for food but also for medicinal and symbolic purposes, associating them with wisdom and abundance.
Hazelnuts have a wide distribution, native to the Northern Hemisphere, particularly in North America, Europe, and Asia. The American hazelnut grows throughout the eastern U.S. and parts of Canada, while the European hazelnut is widespread across the continent and has become the main species used in global commercial production. In Asia, hazelnut species are found from the Caucasus to China and the Himalayas.
Today, Turkey is the world’s leading producer of hazelnuts, especially along the Black Sea coast where the climate is ideal for cultivation. Other major producers include Italy, the United States (primarily Oregon), and Spain. Modern cultivars have been bred for disease resistance, larger nut size, and adaptability to different climates and growing conditions.
Hazelnut trees prefer well-drained, loamy soils and grow best in temperate climates with cool winters and mild summers. They typically begin bearing nuts after three to five years and can continue producing for decades. The trees are wind-pollinated, and most cultivars require cross-pollination to produce viable nuts, which means multiple varieties must be planted together.
The nuts themselves are encased in a hard shell and a leafy husk, and are prized for their sweet, rich flavor and high oil content. Hazelnuts are consumed raw, roasted, ground into pastes, or used in baked goods, candies, and spreads like Nutella. In addition to human consumption, the nuts are a valuable food source for wildlife, including squirrels and birds.
Beyond food, hazelnut trees have other uses. Their wood is flexible and durable, traditionally used for making baskets, walking sticks, and fencing. In some regions, hazelnut hedgerows are also planted for erosion control and habitat restoration. Their dense growth provides excellent shelter and nesting sites for various small animals.
As a crop, hazelnuts are gaining popularity due to growing consumer demand for plant-based, nutrient-rich foods. Rich in vitamin E, healthy fats, and antioxidants, hazelnuts are seen as a sustainable and healthful nut choice. With ongoing breeding programs and climate-adapted varieties, hazelnut cultivation is expected to expand into new regions in the coming decades.
Hazelnut Trees
American Hazelnut (Corylus americana)
Native to the eastern United States, the American hazelnut is a multi-stemmed shrub reaching 10–15 feet tall. It has rounded, serrated leaves, and produces small, edible nuts encased in a leafy husk. It thrives in woodlands and along forest edges and is tolerant of cold climates.
Beaked Hazelnut (Corylus cornuta)
Found across northern North America, the beaked hazelnut gets its name from the long, tubular husk surrounding the nut, which resembles a bird’s beak. It grows as a large shrub with oval, double-serrated leaves, and prefers shady, moist woodland habitats.
European Hazelnut (Corylus avellana)
The most widely cultivated species for commercial nut production, this European native has rounded, hairy leaves and produces clusters of nuts in papery husks. It can grow as a large shrub or small tree and thrives in temperate climates. Cultivars of this species are used for hazelnut orchards worldwide.
Turkish Hazelnut (Corylus colurna)
Also called the Turkish filbert, this species is unique for being a tall, single-trunked tree rather than a shrub. It can grow over 60 feet tall and has deeply furrowed bark, broad serrated leaves, and nuts enclosed in a frilly, deeply-lobed husk. It’s often used in landscaping due to its symmetrical form and drought tolerance.
Asian Hazelnut (Corylus heterophylla)
Native to East Asia, including China, Korea, and Japan, this species resembles European hazelnut but has more variable leaf shapes, hence the name “heterophylla.” It’s cold-hardy and produces edible nuts with thick shells. It’s occasionally used in hybrid breeding for disease resistance.
Himalayan Hazelnut (Corylus jacquemontii)
This rare species from the Himalayan region grows as a shrub or small tree with broad, lobed leaves and distinctive thick, shaggy bark. It produces edible nuts, although they are not widely harvested. The plant is used in reforestation and soil stabilization in high-altitude areas.
Chinese Hazelnut (Corylus chinensis)
Native to central China, this tall-growing species has large, rough leaves and nuts enclosed in heavily fringed husks. It’s not commonly cultivated for nuts but is sometimes used for ornamental planting and hybridization purposes.
Caucasian Hazelnut (Corylus colchica)
Originating from the Caucasus Mountains, this species is adapted to cool, moist climates and is a low, shrubby plant with densely packed leaves and small, sweet nuts. It is rarely grown commercially but has been used in breeding for improved nut quality.
Tombul Hazelnut (Corylus avellana ‘Tombul’)
A leading Turkish cultivar, ‘Tombul’ is prized for its large, round, thin-shelled nuts with high oil content. The shrub is compact, productive, and widely used in the global hazelnut trade. It’s adapted to Mediterranean climates.
Barcelona Hazelnut (Corylus avellana ‘Barcelona’)
Popular in the Pacific Northwest, this cultivar produces large, flat-round nuts and is valued for its vigorous growth and good nut quality. It has broad, dark green leaves and is often used in commercial orchards in the U.S.
Ennis Hazelnut (Corylus avellana ‘Ennis’)
Known for its very large, high-quality nuts, ‘Ennis’ is a European cultivar often grown in Oregon. The tree has a spreading habit and glossy leaves. It requires pollinizers for good nut production and performs best in cool, temperate climates.
Jefferson Hazelnut (Corylus avellana ‘Jefferson’)
Developed in the U.S. for resistance to Eastern Filbert Blight, ‘Jefferson’ is a productive cultivar with large, attractive nuts. The tree has a rounded, symmetrical canopy and shows good resistance to common hazelnut diseases.
Yamhill Hazelnut (Corylus avellana ‘Yamhill’)
A compact and productive cultivar bred for disease resistance, ‘Yamhill’ has dense foliage and medium-sized nuts. It is often planted in orchards where space is limited. Its kernels are of excellent quality and often used in confectionery.
Delta Hazelnut (Corylus avellana ‘Delta’)
A newer cultivar designed for improved resistance and higher yields, ‘Delta’ features upright growth and produces consistently shaped nuts. It is suitable for mechanical harvesting and is increasingly adopted in modern hazelnut farming.
Tonda di Giffoni (Corylus avellana ‘Tonda di Giffoni’)
An Italian cultivar famous for its round, uniform nuts with thin shells and excellent flavor. It is highly valued in the confectionery industry and performs well in Mediterranean climates. Its trees are bushy and produce reliably once established.
Tonda Romana (Corylus avellana ‘Tonda Romana’)
Another well-known Italian variety, ‘Tonda Romana’ features nut clusters with easy-to-shell kernels. It has a strong, upright growth habit and is often grown in combination with other cultivars for pollination. Its nuts are slightly flattened and favored for roasting.