1202 Corylus avellanaCommon Names: European hazel, European filbert, cobnut, Harry Lauder's walking stick Family: Betulaceae (birch Family)
The European hazel or filbert can be a small tree up to 30 ft (9 m) tall, but is more commonly a large shrub to 15 ft (4.5 m) tall with many branches and basal shoots often forming a thicket up to 15 ft (4.5 m) wide. The bark on large trunks is pale grayish brown and peels in long thin coiling strips. The deciduous leaves are alternate, broadly heart shaped, 2-4 in (5-10 cm) long and 1.5-3 in (37-75 mm) wide. They are pubescent beneath, pointed at their tips and have doubly toothed margins. Leaves turn dull yellow, sometimes reddish, in autumn. Male and female flowers are produced on the same trees just before the leaves unfold in early spring. The male catkins, in clusters of 2-5, are pendulous, 2-4 in (5-10 cm) long, yellowish brown and quite showy. Female flowers are football shaped and much smaller, only about 0.2 in (5 mm) long. They give rise to clusters of 1-5 ovoid husks, each enclosing about ¾ of an acorn shaped nut, about 0.8 in (2 cm) long. The edible nuts ripen 7–8 months after pollination and fall to the ground.
Nowadays you’ll be hard pressed to find the natural wild European hazel in the horticultural trade. Instead, this species is primarily known by its cultivars. Ornamental cultivars include ‘Aurea’ with leaves that are bright yellow when young, turning yellowish green as they age; ‘Contorta’ with weirdly twisted branches and shoots; ‘Fusca-rubra’ with purplish foliage; and the weeping cultivar, ‘Pendula’, which is a small tree with branches that arch and then hang to the ground.
Several cultivars are grown commercially for their edible nuts. Many of these are of hybrid origin, resulting from crosses between European hazel and giant filbert (C. maxima), also from Europe. ‘Barcelona’ and ‘Du Chilly’ are perhaps the most important, with ‘Daviana’ usually planted as the obligate pollinizer. [Pollinizer: the plant that produces pollen for another plant; Pollinator: the agent or vector that delivers pollen from a stamen (male flower part) to a stigma (female flower part), often an insect.]
Gardeners in the eastern U.S. who want to grow their own hazelnuts for food have a few selections from C. avellana X C. americana crosses. Among these are ‘Bixby’, ‘Potomac’, ‘Buchanan’ and ‘Reed’.
Corylus avellana occurs naturally in the understory of hardwood and mixed forests throughout much of Europe and western Asia, and in adjacent parts of northern Africa and Iran. It is cultivated commercially for the edible nuts in Italy, Spain, Iran, the Willamette Valley in Oregon, and especially in Turkey which alone produces more than half of the world’s production.
Light: Grow European hazel in full sun to light shade. Cultivars with yellow or purple leaves do best in full sun. Moisture: European hazel likes a well drained soil and has a wide tolerance for soil pH, from acidic to alkaline. Water regularly for the first year after planting out. Hardiness: USDA Zones 4 - 9 . Propagation: Seeds should be sown as soon as they ripen in autumn; if older seed is used it should be chilled for two or three months before planting. Cultivars of European hazel are grafted onto seedlings of the species or propagated by layering. Cultivars are not self-fertile and two different selections are required to produce nuts.
European hazel usually is grown for its handsome yellow male catkins and colorful young foliage. Edible nuts are a bonus. In late winter and early spring, while still mostly leafless, European hazel is especially attractive, hung as it is with myriads of slender pretty yellow catkins.
European hazel can be pruned to a central leader if you want a treelike form for a specimen, or it can be allowed to grow itself into a much branched, bushy shrub as wide as it is tall, and best suited to the shrub border or naturalistic woodland garden. The crooked corkscrew-like framework of the cultivar ‘Contorta’ makes an especially attractive statement in winter when it’s not obscured by foliage. The twisted twigs are useful in arrangements, too (hence the Cut icon).
European hazel has been used (and cultivated) for millennia for thatching and for making walls and fences by weaving sticks together and cementing with mud, clay, or animal dung, a type of construction called wattle and daub. Cultivation and harvest were by coppicing, in which trunks are cut off near ground level, causing each stump to resprout many more stems which can be harvested, and the process repeated. The suckering tendency of European hazel has been put to good use in hedge rows, especially in the British Isles and northern Europe.
The nuts of European hazel, among the largest of the hazels and filberts, are much appreciated in Europe where they are available everywhere food is sold. Nuts are eaten raw, roasted or ground into a paste to be used in cooking and as flavoring. In the New World, production of hazelnuts is pretty much limited to the Willamette Valley in Oregon where the commercial groves are run like sterile factories. The whole process is mechanized, from the tree planting in uncontaminated, flat rows, to the harvesting of the fallen nuts by machine vacuuming.
Attempts to grow European hazel on a commercial scale in the eastern U.S. have not succeeded because of climatic inadequacies and endemic fungal diseases. However, European hazel has been crossed with the American filbert (C. americana), which is tolerant of the fungal blight. Several selections are now available which hold promise for a commercial industry and allow the home gardener to grow his own filberts. At least two different cultivars must be planted within a few yards (meters) of each other to insure cross pollination and adequate nut production.
There are a dozen or so species of hazels and filberts (genus Corylus), all native to north temperate regions. American filbert (C. americana) is a multi-stemmed shrub that grows in the understory of hardwood forests in the eastern U.S. All of the Corylus species produce edible nuts (hazelnuts or filberts – you choose). However, only European hazel (C. avellana) and giant filbert (C. maxima) and their selected hybrids are commonly cultivated on a commercial scale.
Steve Christman 11/5/13