The common hazel grows to a height of between 3 and 8 metres, although it can reach 15 metres. The rounded leaves are deciduous and between 6 and 12 centimetres long. The flowers appear very early in spring, before the leaves. The common hazel produces nuts in clusters of one to five, each one held in a husk that encloses about three-quarters of the nut. Moths and caterpillars feed on the leaves, while the nuts are food for both invertebrates and vertebrates. Invertebrates lay their eggs inside the flowers, while vertebrates such as squirrels and birds are able to crack open the shells. The common hazel is found in hedgerows and was once grown for use in agricultural fencing and traditional building.
The common hazel is native to Europe and western Asia, from the British Isles south to Iberia, Greece, Turkey and Cyprus, north to central Scandinavia, and east to the central Ural Mountains, the Caucasus, and northwestern Iran.