Filbert trees, also known as hazelnuts, offer a rewarding addition to home gardens, providing both aesthetic appeal and a harvest of nutritious nuts. Understanding their needs, from planting to harvest, helps ensure a successful growing experience.
What Are Filberts
Filbert is a common name for plants belonging to the genus Corylus, which are deciduous shrubs or small trees within the birch family (Betulaceae). The term “filbert” is often used interchangeably with “hazelnut,” though “filbert” specifically refers to cultivated varieties, particularly those where the husk fully encloses the nut. These plants are native to the northern temperate zone, including Europe, western Asia, and North America.
Two prominent species are the European Filbert (Corylus avellana) and the American Hazelnut (Corylus americana). European filberts typically grow as multi-trunked shrubs or small trees, reaching heights of 10 to 20 feet. American hazelnuts are generally smaller, growing 9 to 12 feet tall, and are known for their cold hardiness. Filbert plants feature rounded to ovate leaves, often with serrated edges, and produce distinctive male catkins and inconspicuous female flowers in late winter or early spring before the leaves emerge.
Planting Filbert Trees
Filberts thrive in full sun, requiring at least eight hours of direct sunlight daily for optimal nut production. Well-drained, fertile soil with a pH between 6.0 and 7.0 is ideal. Avoid heavy clay or poorly drained areas, as these hinder root development.
Planting is typically done in the spring, using bare-root saplings or potted shrubs. Dig a hole that is twice as wide as the root ball and deep enough so the soil line of the tree is even with the surrounding ground. For bare-root trees, ensure the roots are thoroughly wet before planting. Backfill the hole with enhanced soil, tamping firmly to remove air pockets, and water deeply after planting.
Cross-pollination is essential for good nut production in most filbert varieties, as they are self-incompatible. Plant at least two different compatible varieties to ensure successful pollination. Space trees 15 to 20 feet apart to allow for mature size and adequate airflow, which helps prevent fungal diseases. For best pollination, compatible varieties should be planted within 50 to 200 feet of each other.
Filbert Tree Care
Consistent watering is important for young trees, especially during dry periods. Established trees benefit from deep soaking once or twice weekly during hot, dry summers, ensuring water reaches a foot deep into the soil. Avoid frequent, shallow watering, which can lead to a wet surface but dry root zone.
Filbert trees generally do not require heavy fertilization if planted in good soil. If slow growth or pale leaves are observed, a balanced fertilizer with a mild nitrogen rate, strong phosphorus, and potash (such as an 8-16-16 blend) can be applied in early spring to encourage leaf and root growth, as well as flower and fruit production. Mulching around the base of the tree helps retain soil moisture and suppress weeds.
Filberts naturally grow as multi-stemmed shrubs, but can be trained into a tree form by selecting a few strong central leaders and removing lower branches. Regular removal of suckers that emerge from the roots is important to prevent the plant from becoming a dense, tangled shrub. Pruning dead, damaged, or crossing branches in late winter or early spring, while the tree is dormant, improves air circulation and sunlight penetration.
Filbert trees can be susceptible to certain pests and diseases. Eastern Filbert Blight, a fungal disease, can be serious for European filberts, causing cankers that may girdle and kill branches or even the entire tree. American hazelnuts show more resistance to this disease. Other potential issues include aphids, which can cause leaf curl and sooty mold, and various leafrollers. Inspecting trees regularly and maintaining good cultural practices, such as proper watering and pruning, can help prevent many problems.
Harvesting Filberts
Filbert nuts are ready for harvest from late August through October, depending on the variety and region. An indicator of ripeness is when the nuts begin to fall naturally from the tree. To facilitate harvesting, the area around the trees can be mowed to clear grass and weeds, making it easier to rake fallen nuts into piles. Gently shaking the tree limbs can also help dislodge ripe nuts.
After collection, the nuts require drying or curing to ensure proper storage and flavor development. Spread the nuts in a single layer on a screen or in a well-ventilated area, such as a garage, for several weeks. This process reduces moisture content and improves kernel quality. The nuts are sufficiently dry when the kernel is cream-colored and firm.
Once dried, filberts can be stored in their shells in a cool, dry place, or in an airtight container in the refrigerator for up to a year, or frozen for longer durations. Hazelnuts are enjoyed raw, roasted, or incorporated into various culinary applications, including baked goods, salads, and nut butters.