A large, twiggy shrub or small tree, the hazel tree (Corylus avellana) is regarded mostly as a naturalistic "wild" plant, although some well-shaped and ornamental varieties are popularly displayed in gardens. A member of the birch family, Betulaceae, it bears yellowy flowers that yield edible dry fruits in husks, commonly called filberts. Grow a hazel tree in U.S. Department of Agriculture winter hardiness zones 4 through 8.
The hazel tree's native range extends from Great Britain and Scandinavia eastward to Russia's Ural Mountains The southernmost extent in Europe includes Spain, Italy and Greece. The tree also grows naturally in Morocco and Algeria in northwestern Africa and in Turkey, Iran and the Caucasus in western Asia. The hazel tree grows in oak and conifer forests.
Growing 12 to 20 feet tall and equally as wide, hazel trees attain an upright, rounded shape thanks to many stems rising from the roots, creating a thicket. In late winter to very early spring, the plant flowers with two different flowers. The male flowers occur in yellow pendent spikes called catkins, usually in groups of three on branch tips. The tiny, inconspicuous female flowers also open and are pollinated by the wind to later form and ripen into dry fruits, filberts, that are about three-quarters inch in size. After the early spring flowering, the leaves emerge. They are oval and have edges with many serrations and mature to a deep green. In autumn the foliage attains tones of red and bronze before falling off.
Plant hazel trees in any soil that is not overly wet; it tolerates both infertile and dry soil types well and is a good shrub choice for alkaline soil types. It develops into a nicely shaped plant and flowers best in abundant sunshine, if receiving at least six to 10 hours of direct sunlight daily. It can be grown in partially shaded locales, too, such as among shrubs in sunny openings under woodland trees. In moist, fertile soils there may be a tendency for lots of suckering stems shoots to sprout up from the roots, creating a wild-looking thicket.
Although filbert nuts are edible, hazel trees today are mainly grown and pruned back severely each year to harvest the smooth reddish-brown stems, which have toughness and elasticity. The wood makes hampers, hoops, wattles, shepherds' crooks, walking sticks, fishing rods, whip handles and other rustic items such as seats and baskets for gardens. After burning, hazel tree wood makes good charcoal, from which crayons and gunpowder are made, according to Trees for Life. The hazel tree is regarded as one of the sacred plants of Druids and modern pagan Wiccan groups. In Celtic folklore the filbert nuts are a symbol of mystical wisdom.
While the wild form of hazel tree is not typically used in a garden setting, more ornate varieties exist for this use. The University of Connecticut mentions that the selection Contorta, known as Harry Lauder's walking stick, is the most widely grown hazel tree form in the United States and often the only type available from plant nurseries. Contorta develops spiral branches that are particularly valued by gardeners for textural interest in winter and when flowers appear in early spring before leaves appear. Other ornamental varieties include Aurea with yellow-green leaves; purplish leaves form on both Rote Zeller and Fusco-rubra and Pendula develops weeping branches and forms a cascading, arching shrub. Pendula is usually grafted onto a wild hazel tree or other filbert species' rootstock.