Family: Corylaceae
Common Name: Hazelnut, Filbert

While mostly grown for their nuts, these hardy, deciduous trees and shrubs from temperate regions of the northern hemisphere also work well as ornamentals, screens and windbreaks. Catkins produced by the male flowers and twisted branches of some species are used in floral art. Contorted hazels also make interesting bonsai specimens.

Species

C. avellana, common hazel, zone 4, grows to 5 m (16 Et). Cultivar 'Aurea' has golden leaves; 'Contorta' (syn. 'Harry Lauder's Walking Stick' or 'Crazy Filbert') has incredibly twisted branches.

C. chinensis, Chinese hazel tree, zone 6, reaches heights of 40 m (130 it).

C. colurna, Turkish hazel tree, zone 4, grows to 25 m (80 ft).

C. maxima, giant filbert tree, zone 5, is the species grown commercially, mostly in the United States. It grows to about 5 m (16 ft). Cultivar 'Purpurea' is one of the few shrubs which will grow in heavy clay and dense shade. Reaching 3-1 m in height, it has handsome, heavily veined, dark purple leaves.

Cultivation

Two trees are necessary for pollination and the production of nuts. Hazelnut trees are wind-pollinated so trees should be planted in blocks. Planting several different cultivars should ensure heavier cropping. Propagate by planting nut seeds, or by layers, suckers or cuttings. Layering is considered the easiest method.

Climate

There are species suited to various climatic zones.