Overview of Corylus avellana
Corylus avellana, commonly known as the Common Hazel, is a deciduous shrub native to Europe and western Asia. It has been cultivated for thousands of years for its nuts and wood, and is now a widely-used ornamental plant in gardens and landscaping.
Appearance
The Common Hazel typically grows up to 12 feet tall and 10 feet wide, although it can be pruned to a smaller size. It has a rounded shape with multiple stems that grow from the base. The leaves are broadly oval-shaped, and have a rough texture with serrated edges. In the early spring, the shrub produces long, yellow catkins that eventually open up to reveal tiny red flowers.
Uses
The most well-known use of Corylus avellana is for its nuts, which are commonly called hazelnuts or filberts. The nuts are used in a variety of culinary applications, such as in confectionery, baking, and as a flavoring in coffee. The wood of the shrub is also valuable and has historically been used for making handles, furniture, and walking sticks. Additionally, the shrub is now widely planted as an ornamental in gardens and landscaping because of its attractive shape and foliage.
Growth Conditions of Corylus avellana
Light Requirements: Corylus avellana thrives well in full sun to partial shade conditions. However, it prefers a location with partial shade conditions, especially during hot summer seasons. The plant can also grow well in regions with dappled shade or a few hours of direct sunlight daily.
Temperature Requirements: Corylus avellana adapts and grows well in cool to warm climatic conditions. Temperatures ranging between 4°C to 27°C are ideal for the Corylus avellana plant growth and development. The plant can also tolerate mild frost and cold winter seasons, although protection should be provided for young plants.
Soil Requirements: Corylus avellana thrives well in well-draining, moist, and fertile soils. However, it can grow in a wide range of soil types, ranging from sandy loam to heavy loam soils with a pH of 6.0 to 7.0. The plant prefers slightly acidic to neutral soils, and it cannot tolerate highly alkaline soils.
Water Requirements: Corylus avellana requires moderate watering during the growing season. Watering should be done deeply and thoroughly, ensuring that the soil is moist but not waterlogged. Young plants require more frequent watering than mature plants.
Nutrient Requirements: Corylus avellana requires moderate feeding with a balanced fertilizer to promote healthy growth and development. The application of organic fertilizers can improve soil fertility and plant growth. The plant requires higher levels of phosphorus and potassium and lower levels of nitrogen
Other Requirements: Equally important, Corylus avellana requires proper pruning to remove damaged, diseased, or dead wood, making space for new growth and improving plant vigor. Removal of suckers and shoots is also essential to prevent overcrowding and enhance air circulation. Mulching is equally important in retaining soil moisture, suppressing weed growth, and providing nutrients to the plant as the mulch decomposes.
Cultivation
Corylus avellana, commonly known as the hazelnut tree, grows best in well-drained soils with a pH level of 5 to 7.5. They prefer full sun but can tolerate partial shade. It is best to plant hazelnut trees in the early spring or late fall. Young trees should be spaced about 12 to 15 feet apart.
Watering Needs
Initially, the soil should be kept moist, but not overly wet. Once the tree is established, it can tolerate some drought. Regular watering is necessary during the dry season to ensure the health and maximum yield of the plant. When watering, be sure to soak the soil to a depth of at least six inches.
Fertilization
Hazelnut trees benefit from fertilization, especially during the first few years of growth. Apply nitrogen-heavy fertilizers in the early spring. Mature trees may require additional fertilization in the summer. Nutrient deficiencies can be identified by the yellowing of leaves. It is best to conduct a soil test to determine which nutrients your soil is lacking.
Pruning
Pruning is an essential part of caring for Corylus avellana. It is necessary to remove damaged and diseased branches. It is also essential to prune hazelnut trees to encourage proper growth. Young trees should be pruned immediately after planting to establish a strong structure. Mature trees should be pruned during the dormant season. Remove one-third of the oldest canes each year to ensure healthy and productive growth.
Propagation of Corylus avellana
Corylus avellana, commonly known as the common hazel, is a deciduous shrub with multiple stems that can grow up to 7 meters tall. It is widely grown for its tasty nuts and as an ornamental plant. It can be propagated by various means, including seed, cuttings, layering, and grafting.
Propagation by Seed
Propagation by seed is the easiest method to produce new plants. It is best to collect the seeds in autumn when they are ripe, and the outer husk has turned brown. The nuts can be planted immediately after collection or stored in a cool, dry place. Before planting, the outer husks should be removed, and the seeds should be soaked in water for 24 hours to promote germination. The seeds should then be sown in containers or directly in the ground in autumn or spring.
Propagation by Cuttings
Propagation by cuttings involves taking 15 to 20 cm long cuttings from the new growth of the shrub in summer. The leaves on the lower half of the cuttings should be removed, and the base should be dipped in rooting hormone before planting in compost. The cuttings should be watered and kept in a warm, moist place until roots have developed. After that, the rooted cuttings should be transplanted into individual pots and then planted in the ground the following spring.
Propagation by Layering
Propagation by layering is another simple method that involves making a small incision on a branch in early spring and bending it down to the ground. The bent branch should then be covered at the incision point with soil or compost and then held down with a stone or wire. The tips of the branch should also be exposed to air and sunlight. Roots should develop at the incision point, and the rooted branch can be severed from the parent plant and transplanted the following spring.
Propagation by Grafting
Propagation by grafting is the most challenging method that involves joining a cutting or scion of the desired hazel variety onto the rootstock of another hazelnut plant. This method is typically done in late winter or early spring. The rootstock should be selected for its hardiness and vigor, while the scion should be selected for its desirable characteristics, such as nut size and flavor. After the grafting process, the plant should be kept in a humid, protected environment until signs of new growth appear. Once the new growth appears, the plant can be transplanted in the ground and grown as usual.
Disease and Pest Management for Corylus avellana
Corylus avellana is a deciduous shrub grown for its edible nuts. However, it is highly susceptible to various diseases and pests that can reduce its yield and quality. Therefore, it is imperative to implement proper disease and pest management practices in its cultivation. Here are some common diseases and pests that may affect Corylus avellana and ways to manage them:
Diseases
Bacterial blight - A bacterial disease that causes yellowing and browning of leaves, twig dieback, and sometimes, nut rot. It can be managed by pruning and burning infected plant parts and applying copper fungicides.
Corylus avellana mosaic virus - A viral disease that causes yellowing, mottling, and deformed leaves, as well as reduced nut size and yield. It has no cure, but you can manage it by removing and destroying diseased plants and controlling aphid vectors.
Crown rot - A fungal disease that attacks the roots and stems, causing wilting, yellowing, and eventually, death. It can be managed by improving soil drainage, avoiding overwatering, and using fungicide treatments.
Fusarium wilt - A fungal disease that causes yellowing, wilting, and necrosis of leaves and stems, as well as reduced nut size and yield. It can be managed by practicing crop rotation, using resistant cultivars, and applying fungicide treatments.
Pests
Aphids - Small insects that feed on the sap of leaves, causing curling, yellowing, and stunting. They can be managed by using insecticidal soap, neem oil, or beneficial insects like ladybugs and lacewings.
Codling moth - A moth whose larvae bore into the nuts, causing them to rot and drop early. It can be managed by using pheromone traps, timing insecticide applications before egg-laying, and releasing parasitic wasps.
Filbertworm - A caterpillar that feeds on the nuts, causing kernel damage and early drop. It can be managed by using insecticide treatments during the vulnerable period, maintaining orchard hygiene, and releasing parasitic wasps.
Mites - Small arthropods that suck sap from leaves, causing yellowing and leaf drop. They can be managed by using miticides, increasing humidity, and avoiding excessive nitrogen fertilization.
Implementing proper disease and pest management practices is crucial in maintaining the quality and yield of Corylus avellana. A combination of cultural, biological, and chemical control methods can help prevent and manage damage caused by diseases and pests.
