The common hazel, a member of the birch family (Betulaceae), is native to Europe and Western Asia
. It is a small deciduous tree with multiple stems, which attain a height of 3 to 8 meters.
The flowers of common hazel are produced before the leaves and start blooming as soon as February. They are monoecious, which means that both male and female flowers can be found on the same tree. Pollination of hazel is by wind. It only takes place between different trees [a single tree cannot pollinate itself]. The male catkin, also called ‘Lamb’s tail’, is yellow in colour and 5 to 12 centimeters long. The female catkin is quite small and remains concealed in the buds in such a way, that only the red coloured styles are visible.