Basic Information

Common Name: Hazel

Scientific Name: Corylus

Native Habitat: Europe, Western Asia

History / Discovery / Cultivator

The hazel, belonging to the genus Corylus, has a rich and interwoven history with human civilization. Its earliest interactions can be traced back to prehistoric times, with archeological evidence indicating the consumption of hazelnuts by humans as far back as 8000 BC. These early humans likely gathered the nuts from wild hazel trees in their native habitats across Europe and Western Asia.

The process of cultivating hazel trees is thought to have begun independently in different regions, with early agricultural societies recognizing the value of the hazelnut as a food source. Ancient Roman writers, such as Pliny the Elder, described different varieties of hazelnuts and their cultivation techniques, suggesting that the Romans were actively involved in the propagation and improvement of hazel trees.

In medieval Europe, hazelnuts played an important role in both subsistence and cultural practices. Hazel trees were often planted in orchards and were valued for their nuts, which provided a source of food during the winter months. The wood from hazel trees was also used for a variety of purposes, including crafting wattle fencing, tool handles, and even divining rods.

The hazel tree also holds a significant place in mythology and folklore. In Celtic traditions, the hazel tree was associated with wisdom, knowledge, and inspiration. It was believed that eating hazelnuts could grant one access to hidden knowledge, and hazel wands were often used in divination practices. In Norse mythology, the hazel tree was associated with the god Thor, and its branches were said to offer protection from lightning.

Over the centuries, different cultivars of hazel trees have been developed to enhance nut production and improve disease resistance. The “Barcelona” hazelnut, for example, is a popular cultivar known for its large, high-quality nuts. The “Cosford” hazelnut is another notable variety, valued for its thin shell and sweet flavor. The development and cultivation of these improved cultivars have significantly contributed to the commercial production of hazelnuts around the world. Modern cultivation practices have expanded beyond Europe and Western Asia, with significant hazelnut production now occurring in regions like Turkey, Italy, and the United States (Oregon).

The hazel continues to be appreciated for its versatility, from its edible nuts to its durable wood, and its deep-rooted connections to human history and culture. Its cultivation persists as a blend of tradition and innovation, ensuring its presence in our lives for centuries to come.

Plant Care Summary

Botanical Insights

Adaptations

Hazel trees exhibit several adaptations that allow them to thrive in their native environments. One notable adaptation is their ability to tolerate a wide range of soil conditions, from well-drained loams to slightly acidic soils. This adaptability allows them to colonize diverse habitats, from woodlands to hedgerows.

Another important adaptation is their ability to produce nuts, which serve as a valuable source of food for both humans and wildlife. The hard shells of the hazelnuts provide protection for the seeds, ensuring their survival and dispersal. Hazel trees also exhibit a remarkable ability to regenerate from their roots, allowing them to recover quickly from damage caused by grazing animals or harsh weather conditions. This resilience makes them well-suited to disturbed habitats and allows them to persist in areas where other trees might struggle to survive.

Propagation Methods

Hazel trees can be propagated using several methods:

• Seed: Hazelnuts can be sown directly in the ground in the fall or stratified and sown in the spring. Seedlings require several years to mature and produce nuts.
• Layering: Layering involves bending a low-hanging branch to the ground and covering it with soil. The branch will develop roots over time and can then be separated from the parent plant.
• Suckers: Hazel trees often produce suckers, which are new shoots that emerge from the roots. These suckers can be dug up and transplanted to create new plants.
• Grafting: Grafting involves joining a scion (a cutting from a desired variety) onto the rootstock of another hazel tree. This method is often used to propagate specific cultivars of hazelnuts.

Toxicology

Hazel is generally considered to be non-toxic. According to the ASPCA, the Hazelnut tree (Corylus species) is not poisonous to dogs, cats, or horses. However, ingesting large quantities of any plant material may cause mild gastrointestinal upset. The primary risk associated with hazelnuts is allergic reactions in individuals with nut allergies. Symptoms of a hazelnut allergy can range from mild itching and hives to severe anaphylaxis, a life-threatening allergic reaction.

Common Problems

Pests:

• Aphids
• Hazelnut Weevil
• Spider Mites

Diseases:

• Eastern Filbert Blight
• Powdery Mildew
• Crown Gall

Other:

• Lack of Nut Production: Insufficient sunlight, poor pollination, or nutrient deficiencies can reduce nut yields.
• Squirrel Predation: Squirrels and other rodents can consume large quantities of hazelnuts before they can be harvested.
• Chlorosis (yellowing leaves): Often caused by iron deficiency in alkaline soils.

Rarity & Value

Rarity:

While the common hazel (Corylus avellana) is not considered rare, certain hazelnut cultivars or specimens with unique characteristics (e.g., unusual leaf shapes, ornamental qualities) might be less common and therefore considered rarer in the horticultural trade. Wild hazels in specific locations may face habitat loss, contributing to localized rarity.

Value:

The value of hazel trees and hazelnuts depends on several factors. For commercial growers, factors such as nut size, yield, disease resistance, and market demand influence value. Ornamental hazel trees with unique foliage or branching patterns may be valued for their aesthetic appeal in landscaping. Rare or unusual cultivars of hazelnuts might command higher prices among collectors.