Saturday, 31 August 2013

Hazelnut (Corylus avellana)

Hazelnut (Corylus avellana) is a hardy deciduous shrub or tree from the Betulaceae or Corylaceae family. Hazelnut is also known as the common hazel, cobnut, European hazel, filbert, hale nut, stock nut, wood mut and Pontic nut. It is native to many parts of the temperate Northern Hemisphere including the British Isles.

An image of a hazelnut (Corylus avellana) shrub
Hazelnut (Corylus avellana)

Hazelnuts grew in deciduous forests around 18,000 and 17,000 B.C, gradually moving north when the glaciers retreated. They have been cultivated in China for more than 5000 years. In the British Isles large scale processing of the nuts was carried out on the Hebridean island of Colonsay as far back as 9000 years ago. The leading producer in the world today is Turkey. Within the UK the largest commercial orchards or 'plats' are produced in Kent. However, they can be successfully grown all over the British Isles.

Hazelnut, cobnut or filbert?

Throughout the world the terms hazelnut, cobnut and filbert are often used to describe any one of several species these days. Hazelnut, in particular, is used to describe most species including the wild forms.

Cobnuts (European or common Hazel) are generally regarded as being derived from Corylus avellana. They have a short husk or papery casing which doesn't completely cover the nut.

Filberts are generally considered to be from Corylus maxima (the Balkan Hazel). They have a long husk or 'full beard' which completely covers the nut. However husk length does depend to a certain extent on the growing conditions as much as the variety.

An image of dried hazelnuts without the shell and husk
Dried hazelnuts without the shell and husk

Corylus are a genus of around 15 species of nuts comprised mainly of deciduous shrubs and trees common to northern temperate regions. The nuts of Corylus avellana, which now has many cultivars, is highly productive and probably more widely grown than most. Hazel cultivars grown today were originally taken from wild species and tend to produce larger nuts and heavier crops. There are many named varieties.


To propagate shrubs the easiest way is to layer them by nicking a branch with a knife and then bending the branch over and pegging the nicked part to the ground to root. Shrubs can also be propagated by air or tip layering or by taking softwood cuttings in June or July and hardwood cuttings in February. It is more difficult to take cuttings and none of our 2012 cuttings took at all.

If you have squirrels, they will clear a shrub of nuts within a very short space of time, eating some and burying most. The nuts that have been buried will often germinate of their own accord and when the little trees appear they can be dug up and transplanted to their final position. Shrubs transplant well even when quite large. Nuts may not grow true to form but we have obtained edible nuts from shrubs grown in this way.

No squirrels? Not to worry! Take fresh seeds and sow immediately in the autumn in a cold frame. Seeds will germinate in the late winter or early spring. To check whether seeds are viable before sowing place them in a bowl of water. Viable seeds will sink.

Ready grown shrubs and trees are available from nurseries throughout the UK and may be a more reliable option if you just want one or two specimens.

An image of a hazelnut shrub planted as hedging
Hazelnut planted as hedging

Growing conditions

Hazelnuts are monoecious and small yellow female flowers and male catkins are produced on the same tree. They are self fertile and wind pollinated. Since male and female blossom is not always produced at the same time, it is more productive to plant different cultivars to ensure a higher degree of pollination. Plant in a square formation to further assist the process.

Hazelnuts like full sun or light shade plus light well drained soil which is kept moist. They will, however, tolerate many soil types and ours grow well in heavy clay soil. Keep the soil moist around the base, watering where necessary. Don't over feed as rich soil can lead to excessive growth. A yearly feed of animal-free organic fertiliser in late winter can be beneficial. Nuts are produced after about 3 - 4 years and on last year's growth.

Hazelnuts are generally disease free but can be attacked by some pests such as nut weevils or Lepidoptera. And squirrels of course.


Hazelnuts can be grown as a single or multi-stemmed shrub or tree. Left unpruned they may grow several metres tall. For an averaged sized back garden it is probably prudent to prune in winter to the desired height and shape. Keep the shrubs or trees open in the centre in a cup shape. In August encourage the tiny female flowers (and therefore more nuts next year) by snapping but not breaking off new top growth. This is a technique called 'brutting' or 'bratting'. Please note that coppicing on a regular basis will stop the crop of nuts for several years and so should not be carried out on trees designated for nut production.

An image of a single Hazelnut shrub planted in a front lawn
A single Hazelnut shrub planted in a front lawn

Storing nuts

Pick the nuts when the outer husks turn a yellow colour in late September. Nuts can be eaten fresh from the tree or stored. To store fresh nuts pack in damp sand and check regularly for mould. They should last 3 or 4 months before they begin to sprout. They can also be dried in the shells by storing in nets or on trays in a dry airy place for several weeks. Shells can also be removed before storing in which case the nuts should be thoroughly dried to between 8 – 10% moisture in a dehydrator before storing in an airtight container.

Raw edible parts

The nuts of all Corylus species are edible raw. Hazelnuts can be eaten fresh from the tree or dried for later use. Most nuts available in shops these days are the dried form. Nuts can be blended with water and sieved to make a milk or pressed to make a raw edible oil. Ground down into a fine powder, they make a good raw flour for cakes, flan bases or biscuits.

Other uses

Hazel wood can be used for furniture, basketry, as dowsing rods, to make artists' charcoal, thatching, fencing, plant stakes or pea sticks. It used to be grown for wattle and daub. The oil from the seed is non-drying and can be used in paints and cosmetics.


  1. This is the only place where I have seen the Hazel tree referred to as self-fertile. Always plant at least two non-clones is the normal advice.

    1. "Cobnuts and filberts are monoecious, bearing separated male (catkins) and female flowers on the same tree. Despite being self-fertile, hazels (cobnuts and filberts) are wind pollinated and crop more reliably when grown in groups. It also helps to plant them in a square formation to maximise pollination." (Royal Horticultural Society, 2014)

    2. Perhaps it is those selling them that claim two or more are required. Given the room though I would certainly opt for 2 or more for better pollination. Thanks for the info!