Hazel is one of our most recognisable native plants, with its rounded lined leaves, pendent catkins and hazelnuts. It is commonly seen in hedgerows and is one of the plants that make up our ancient woodlands. Grown for centuries for its wood, as well as its edible nuts, these trees are still coppiced today to produce poles and pea sticks.
But the genus Corylus is more than just hazel. It also contains the filberts (C. maxima species and varieties) that are so named because their nuts were traditionally harvested on St Philibert’s feast day (20 August). This is earlier than hazelnuts (or cobnuts) are harvested. The way to tell them apart is that cobnuts have short husks while the filberts have husks that are longer than their nuts.
There are 10 species of Corylus and all of them are large shrubs or small trees, native in much of Europe, western Asia and parts of North Africa. They bear both male and female catkins. The male catkins are the showy pendent ones, borne in late winter or early spring. The female catkins are bud-like with red stigmas emerging from the end.
The only other Corylus grown and sold in any number in the UK, alongside hazel (C. avellana) and filbert (C. maxima), is the Turkish hazel, C. colurna Award of Garden Merit (AGM). It is a tidy ornamental tree with a straight stem, quite different from its rangy relatives. It has strong green summer foliage and decorative male catkins in later winter. It is used as a street tree and has fine pinkish-brown timber, which is good for cabinetmaking.
There are a few widely grown varieties, particularly C. avellana ‘Contorta’ AGM, the corkscrew hazel, which has highly twisted twigs and distorted leaves. It creates an incredible winter silhouette.
There are also several good purple-leaved forms, including C. avellana ‘Anny’s Purple Dream’ Plant Breeders Rights (PBR), C. avellana ‘Red Majestic’ PBR/AGM and C. maxima ‘Red Filbert’ AGM. Probably the best is C. maxima ‘Purpurea’, which is said to rival the purple beech for intensity of colour. It even has purple-tinged nuts.
Hazels are easy to grow — they will even tolerate alkaline soils and partial shade. If you are growing them to produce a nut crop, then you will need to plant more than one variety (they are wind-pollinated). Plant them about 4-5m apart. They will start producing nuts after around four years.
Squirrels are a real pest so establish your nuttery in as squirrel-free a location as possible, away from large trees and shrubs in which squirrels like to make their habitat and from where they can jump.
If you intend to leave C. avellana and C. maxima to grow naturally then you may want to annually cut out some of the stems because they can become congested. They can also be coppiced on a three- to 10-year basis, which will provide a good supply of pea sticks, bean poles and firewood.
What the specialists say
Matthias Anton, managing director, Deepdale Trees, Bedfordshire
"Corylus is a very good plant for native mixed hedgerows. It is also perfect as a specimen or clipped into an umbrella-shaped specimen. The species or varieties that stand out for me are the native hazel, C. avellana; twisted hazel, C. avellana ‘Contorta’; and Turkish hazel, C. colurna.
"C. colurna is a very good and tough street tree. Once established, it will grow into a nice, dense, healthy tree. It is very drought-resistant as well. C. avellana ‘Contorta’ can be used as a standalone specimen and be pruned into a characterful umbrella."
Simon Scarth, director, Chew Valley Trees, Bristol
"Hazels make good wildlife-friendly shrubs and work well in a mixed country hedge. The yellow catkins offer winter interest and, although not showy, the foliage makes a good screen. It’s best suited to a woodland garden or informal shrubbery, or planted en masse to form a nuttery.
"For something ornamental, purple-leaved cultivars such as C. avellana ‘Red Majestic’ and the filbert C. maxima ‘Purpurea’ are great for a dark splash of colour. The curling stems of C. avellana ‘Contorta’ are good for winter interest and floristry material. It originates from just outside Bristol, where it was spotted in a hedgerow in the 1860s by the Victorian gardener Canon Ellacombe, who propagated and shared it.
"For nuts, we recommend the cobnut ‘Cosford’ and filbert ‘Gunslebert’. The Turkish hazel, meanwhile, is a handsome tree with a corky bark that can grow up to 50ft. It also produces a few nuts, but it’s the regular pyramidal crown and general robustness that recommend it for planting in parks and streets."
Ellen Carvey, retail sales manager, Barcham Trees, Cambridgeshire
"C. avellana is a versatile tree that is generally considered to be native to the UK. It grows extremely quickly and can be planted both as a single shrub or maintained as a collection of trees that form a dense and fast-growing hedge.
"The other up-and-comer in the UK is C. colurna, the Turkish hazel. It has a wonderful shape to it, forming a uniform, pyramidal tree that has the regularity to make not only a useful street tree but an alternative parkland specimen.
"A variety that I particularly like is C. avellana ‘Zellernus’, the red filbert. This is a purple-leaved form that has a lovely deep-purple flush of foliage in the springtime. As the months wear on it does harden to green, but a darker green than the species.
"Throughout the winter months this variety produces large pink-coloured catkins that hang gracefully in the gloom of winter. Like the common hazel, this species has a shrubby, rather than tree, form that can be routinely coppiced to maintain the size."
Amanda Patton, garden designer, Amanda Patton Landscape & Garden Design, Sussex
"It isn’t a plant I use that much as it doesn’t really have much form. But where I have used it is to create the lower-storey ‘middle fluff’ in a woodland planting scheme, either in existing woodland where I want to add more interest at mid level or in a new scheme where I want to blur the boundary to what’s beyond.
"I have also used cobnuts, planted in an avenue, in a more traditional nuttery and as a useful feature — because it has some formality — to link garden to informal."
Species and varieties
C. avellana is our native hazel, a large shrub or small many-stemmed tree. It has rounded leaves that turn yellow in autumn and long yellow male catkins in early spring, followed by edible nuts in autumn. Height: 4-8m.
C. avellana ‘Anny’s Purple Dream’ PBR is an unusual hazel that grows to be a conical small tree with lovely dark-purple summer leaves. It can be coppiced to create a smaller, more branching shrub. Produces a good crop of edible nuts once established. Height: 8-10m. Spread: 3-4m.
C. avellana ‘Contorta’ AGM (H6), or the corkscrew hazel, is a fantastic feature shrub because of its highly contorted and twisted branches. These show beautifully during the winter when its yellow male catkins hang. A favourite of florists. Height and spread: 5m.
C. avellana ‘Cosford’ produces a nice edible nut and is a good pollinator for other cultivars, making them a good choice for a nut orchard. Height: 2-3m.
C. avellana ‘Red Majestic’ PBR/AGM (H6) is a compact, spreading to semi-weeping small tree with dark-purple leaves, becoming green flushed as the season progresses, and twisted branches. In late winter it bears purplish-pink catkins. Height and spread: 4m.
C. colurna AGM (H5), the Turkish hazel, is a medium to large-sized deciduous tree of very symmetrical, pyramidal form. It has slightly lobed broadly ovate leaves and pendulous yellow catkins. The corky corrugations of the bark are an attractive feature. Height: 20m.
C. maxima is the filbert, a large shrub or small spreading tree that has larger and longer nuts than C. avellana. Its leaves are large, rounded and heart-shaped. Height: 6m. Spread: 5m.
C. maxima ‘Kentish Cob’ is a reliable variety producing well-flavoured nuts. It has broad green leaves and pale-yellow catkins. Height and spread: 2.5-4m.
C. maxima ‘Red Filbert’ AGM (H6) is a form with nicely coloured burgundy-to-purple foliage as the leaves emerge in spring, becoming dark-green as the season progresses. It also has purplish-pink catkins in winter that are followed by edible red nuts in the autumn. Height: 4-8m. Spread: 2.5-4m.
C. maxima ‘Purpurea’, the purple-leaved filbert, is a large deciduous shrub with broad deep-purple leaves. Pale-yellow catkins hang on leafless twigs in late winter, followed by edible nuts concealed by a tubular husk. Rivals the purple beech for intensity of colour. Height: 4-8m. Spread: 2.5-4m.
Thank you to Floramedia, which supplied the images for this article from its photo library