Filbert trees, also known as hazelnuts, are a popular choice for home gardeners seeking both an attractive landscape plant and a rewarding annual nut harvest. These adaptable members of the Corylus genus are naturally hardy, thriving across a wide range of climates and soil types. Cultivating filberts involves managing their natural tendency to grow as a multi-stemmed shrub while directing energy toward producing the highly valued nuts. Success begins with understanding the specific environmental needs required for long-term production.
Site Selection and Initial Planting
Selecting the right location is important, as filbert trees require full sun exposure, meaning a minimum of six to eight hours of direct sunlight each day. The soil should be fertile and consistently well-drained, ideally with a loamy or sandy-loam texture to prevent standing water and root rot. Filberts perform best in a slightly acidic to neutral pH range, typically between 6.3 and 6.8.
When planting, dig a hole two to three times wider than the root ball, ensuring the top root is covered by two to three inches of soil after settling. This shallow planting encourages the tree’s natural surface-rooting habit. Plan for a final spacing of 15 to 18 feet between trees to allow for mature canopy growth.
Cross-pollination is required for nut production, as filberts are not self-fertile despite having both male and female flowers. Growers must plant at least two different, compatible varieties within 50 to 100 feet of each other. Choosing varieties with overlapping bloom times is necessary for reliable fertilization and nut set.
Essential Maintenance Practices
Newly planted filberts require careful attention to watering for the first two to three years while their root systems establish. Provide about one inch of water per week through deep, infrequent soakings. During dry or hot periods, supplemental watering is necessary to keep the soil consistently moist but never saturated.
Mulching helps conserve soil moisture, suppresses weeds, and moderates soil temperature fluctuations. Apply a three to four-inch layer of organic mulch, such as wood chips or pine needles, extending outward to the tree’s drip line. Leave a small ring of bare ground immediately around the trunk to prevent moisture retention against the bark, which can encourage decay.
Avoid fertilization during initial planting to prevent root burn; wait until the second year before starting a feeding regimen. Mature trees benefit from an annual application of a balanced fertilizer, such as a 20-20-20 blend. Apply the fertilizer in late fall after leaf drop or in early spring before bud break, spreading it evenly across the soil surface at the drip line.
Structural Pruning for Yield
Filbert trees naturally grow as multi-stemmed shrubs, often called the “bush” or “ocak” system, but they can be trained into a single-trunk tree form. The primary goal of structural pruning is to establish a strong scaffold framework during the first three to five years and maintain light penetration. Pruning is most effective during the dormant season, typically in late winter, as this timing stimulates vigorous growth the following spring.
A regular task is the removal of suckers, which are vigorous, non-fruiting shoots emerging from the roots or trunk base. Suckers compete for nutrients and should be removed immediately, preferably by tearing them off the root system. For mature trees, thinning cuts remove older, less productive wood to encourage the development of new fruiting branches.
To maximize nut yield, the center of the canopy must remain open to sunlight. This is achieved by annually removing one to three upright limbs or any crossing branches that impede air circulation. This thinning ensures sunlight reaches all parts of the tree, which is necessary for flower bud initiation and consistent nut production. Heavy pruning should be done gradually, removing no more than 25 to 30 percent of the living canopy in any single year.
Protecting Trees from Pests and Disease
Filbert trees are susceptible to fungal diseases, which pose the greatest threat to harvest health. Eastern Filbert Blight, caused by Anisogramma anomala, manifests as dark, football-shaped cankers on the branches. If infection is observed, immediately prune out the infected wood, cutting two to three feet below the visible canker. Sterilize pruning tools with a 10% bleach or 70% alcohol solution between cuts to prevent spread.
Bacterial blight, caused by Xanthomonas corylina, creates water-soaked lesions that turn reddish-brown on the leaves and can progress into cankers that girdle young twigs. Management requires the prompt removal of infected material, cutting six to eight inches beyond the visible symptoms. Orchard sanitation and good air circulation are the best preventative measures against both blights.
Common insect pests include aphids and filbert bud mites, which reduce tree vigor and nut quality. Aphids cluster on new growth, sucking plant juices and excreting honeydew. Small infestations can often be managed with a strong jet of water or the application of insecticidal soap. Maintaining overall tree health through consistent watering and feeding helps the tree resist major infestations.
Harvesting and Curing Nuts
The final stage begins when the nuts start to ripen in late August and through September. Nuts are ready for harvest when their outer husks turn brown and they naturally drop to the ground. Since the ripening process takes several weeks, the harvest usually occurs over an extended period.
To facilitate collection, clear the ground beneath the tree just before the nuts begin to fall, or place a tarp under the canopy. Gently shaking the branches or sweeping the fallen nuts accelerates collection. Gather the nuts promptly to prevent mold development and deter local wildlife.
After collection, the nuts require curing to reduce moisture content for long-term storage and flavor development. Spread the nuts in a single layer on a screen or rack in a warm, dry area with good airflow, ideally between 90 and 105 degrees Fahrenheit. This drying period typically lasts two to four weeks, after which the nuts can be stored in their shells in a cool, dry place for several months.