Overview
Corylus colurna L. is a deciduous tree species from the Betulaceae family. It is native to southeastern Europe and western Asia but can also be found in North America. The tree has been introduced in many other parts of the world and is commonly grown as an ornamental tree.
Common Names
Corylus colurna L. has several common names, including Turkish Hazel, Turkish Filbert, and Blister Nut. In some regions, it is known as the Constantinople Nut.
Appearance
The Turkish Hazel grows up to 20-30 meters tall and has a broad, rounded crown. Its bark is grayish-brown, smooth, and often warty. The leaves are oval-shaped, pointed, and have serrated edges. They are about 10-15 cm long and 6-12 cm wide. The tree produces small, yellowish-brown flowers in the spring, which are followed by the fruit- the Blister Nut. The fruit is round, about 2.5 cm in diameter, and covered by a tough, papery covering that gives the tree its common name. The nuts are edible but usually not consumed due to their unpleasant taste.
Uses
Corylus colurna L. is primarily used as an ornamental tree, thanks to its attractive foliage and rounded shape, which make it an excellent shade tree. Its nuts are occasionally used as food, but more commonly used for their wood. The wood is hard and durable, which makes it suitable for furniture, handles, and other woodwork products. Medicinal properties have also been attributed to the tree, with its bark, leaves, and nuts all having historical use in traditional medicine.
Light Requirements
Corylus colurna, also known as the Turkish hazelnut tree, prefers full sun to partial shade. It can tolerate some shade, but it may result in reduced growth and flowering. In areas with hot and dry climates, providing some shade during the hottest part of the day can help protect the tree from heat stress.
Temperature Requirements
Corylus colurna is a hardy tree species that can tolerate a wide range of temperatures. It can grow in USDA hardiness zones 4 to 9, which means it can withstand temperatures as low as -30°F (-34°C) and as high as 100°F (38°C). However, it grows best in temperate climates with cool to mild summers and cold winters.
Soil Requirements
Corylus colurna can grow in a variety of soil types, but it prefers well-draining soil that is rich in organic matter. It can tolerate slightly acidic to alkaline soils with a pH range of 4.5 to 8.5. However, it does not do well in soils that are constantly waterlogged or prone to drying out. The ideal soil for Corylus colurna is a loamy, sandy soil that retains moisture but does not become waterlogged.
Cultivation methods for Corylus colurna L.
Corylus colurna L., also known as Turkish hazelnut, is a deciduous tree that is mainly cultivated for its ornamental value and its delicious nuts. To grow this plant successfully, it is advisable to choose a site with fertile, well-draining soil and ample sunlight. Keep in mind that it prefers slightly acidic soil. The best time to plant Corylus colurna L. is in the early spring or late fall when the soil is moist and the weather is mild.
Watering needs for Corylus colurna L.
Corylus colurna L. has moderate water requirements. A young plant may need regular watering, but once it is established, it should be able to survive with minimal watering. It is important to avoid overwatering this plant as it can lead to root rot. Water the plant deeply once a week during the growing season and reduce watering during the winter months.
Fertilization for Corylus colurna L.
Corylus colurna L. requires regular fertilization to ensure healthy growth and optimal nut production. Apply a balanced fertilizer, such as a 10-10-10 blend, in the spring just before new growth begins. If the soil is deficient in nutrients, use an organic fertilizer to improve soil quality and enhance plant growth. Avoid over-fertilization as it can lead to excessive vegetative growth and reduce nut production.
Pruning of Corylus colurna L.
Pruning is a crucial aspect of Corylus colurna L. care. Prune the tree selectively to remove damaged, diseased, or dead branches. This will help prevent the spread of diseases and pests. Prune the tree in late winter or early spring when the plant is dormant. Avoid excessive pruning as it can stimulate vegetative growth at the expense of nut production. Prune the tree to maintain a balanced shape and to promote optimal light penetration and air circulation.
Propagation of Corylus colurna L.
Corylus colurna L., commonly known as Turkish hazel or Constantinople hazel, is a deciduous tree native to southeastern Europe and southwestern Asia. It is commonly grown as an ornamental tree for its attractive shape and foliage, as well as for its production of edible nuts. Propagation of Corylus colurna L. can be done through various methods.
Seed propagation
The most common method of propagation for Corylus colurna L. is through seeds. The seeds are usually collected during late summer or early autumn and must be sown immediately. The seeds should be sown at a depth of about 2 to 3 times their diameter in a well-draining and fertile soil mix. The soil should be kept moist, but not waterlogged, until the seeds germinate. Germination can take anywhere from 2 to 8 weeks depending on the conditions. Once the seedlings are established, they can be transplanted to their permanent location in their second or third year.
Cuttings propagation
Propagation of Corylus colurna L. can also be done through hardwood cuttings. Hardwood cuttings should be taken during winter dormancy when the plant is leafless. The cuttings should be around 15 to 20 cm in length with 2 to 3 nodes. The cuttings should be treated with rooting hormone and planted in a well-draining soil mix. The soil should be kept moist until roots develop. The new plant can be transplanted to its permanent location in the following year.
Air layering propagation
Air layering is another method of propagating Corylus colurna L. This method involves wounding a branch by removing a small strip of bark and wrapping the area with moist moss and plastic wrap. Roots will develop at the wounded area, which can be severed and planted in a container or directly in the ground. The new plant should be kept moist until it shows signs of new growth.
Grafting propagation
Grafting is a common propagation method for horticultural plants, and it can also be used to propagate Corylus colurna L. This method involves joining a scion, or a shoot of the desired plant, to a rootstock of a closely related species or cultivar. Grafting can be done during winter or early spring when the plants are dormant. The grafted plants should be kept moist and protected until they show signs of new growth.
Regardless of the propagation method used, it is important to note that Corylus colurna L. prefers full sun to partial shade and a well-draining soil that is rich in organic matter. The soil should be kept moist but not waterlogged. With proper care, the new plants can establish quickly and provide years of enjoyment.
Disease Management
Corylus colurna L., commonly known as Turkish hazel, is relatively resistant to many infectious diseases, but various fungal, bacterial, and viral diseases can still occur. It is important to monitor the plant regularly for any signs of disease. Promote good plant health by practicing cultural management techniques such as pruning, controlling weeds, providing adequate drainage, and minimizing wounding.
Common Diseases
Bacterial blights: Xanthomonas campestris can infect leaves, stems, and nuts and can cause yellowing, spotting, and wilting. Erwinia amylovora can infect the flowers, growing tips, and stems causing wilting and blackening of stems.
Fungal diseases: Corylus colurna is vulnerable to several fungal diseases such as leaf spot, cankers, rusts, powdery mildew, and root rot. Leaf spot is a common disease caused by the fungus Mycosphaerella alphitoides. Symptoms include small purple spots on leaves that expand and join together, forming large areas of necrotic tissue. Powdery mildew, caused by Erysiphe corylacearum, produces a white powdery growth on the leaves, flowers, and buds.
Management
Preventative measures such as planting disease-resistant cultivars can reduce the possibility of developing bacterial or fungal diseases. Fungicide and bactericide sprays may be appropriate for some bacterial and fungal diseases.
Prune and remove infected plant parts to promote the plant's overall health and to reduce the spread of diseases. Sanitize pruning tools using 10% bleach solution between plants to prevent the transmission of diseases. Proper cultural control measures such as regular irrigation, improved drainage, and soil aeration can help prevent the occurrence of root rot.
Pest Management
Several insect and mite pests pose potential threats to Corylus colurna. Insect damage can reduce yield, quality, and even result in plant death. Monitor the plants regularly for any signs of insect infestation.
Common Pests
Filbertworm: The larvae of this insect can cause significant damage to the nuts by feeding on them. The damage results in the nuts falling prematurely from the tree, reducing the overall yield.
Hazel aphid: The hazel aphid feeds on the sap of the leaves or nuts, causing leaf curl, yellowing, and stunting of the growth of the plant.
Management
Insecticidal sprays may be necessary to control some insect pests. Natural predators of pest insects, like ladybugs or hoverflies, can be introduced to control aphids without the use of insecticides. Properly timed insecticide applications can control the Filbertworm larvae.
Good cultural practices such as removing and destroying infested plant parts, maintaining plant health, and practicing good sanitation can help prevent infestations from occurring. Horticultural oil sprays may also help reduce pest populations when applied at the appropriate time.
