Corylus avellana - Hazel A native Irish tree, once believed to be the tree of knowledge, Corylus avellana is a large, deciduous shrub or small tree with a spreading, bushy habit. The large, mid-green leaves are broad, almost round, with a serrated edge, and turn yellow in autumn. The long, yellow male catkins appear in January and February; although the tiny, red-styled female flowers appear on the same tree, they must be pollinated by wind-blown pollen from another tree. From September, the hazel-nuts appear, sheathed in a frilly green husk; they are delicious, and highly nutritious – high in protein, mono-unsaturated fat, minerals and Vitamin E. Hazels can be coppiced, and will regrow long stems, ideal as bean-poles. Site: Tolerates exposureSoil: Any light, well drained soil, preferably alkaline or neutralPosition: Full sun or partial shadeSeason of interest: Autumn in particularHardiness: Very hardy Height: up to 26’ (8m) Spread: 26’ (8m) Learn more about how to choose and grow hazelnuts and other nuts in our advice section and on our resources page.