Well known as a tree grown for its cobnuts or hazelnuts corylus avellana is also a fantastic hedging plant elegant yellow catkins hang gracefully along the bare branches in early spring followed by large rounded green leaves which turn to buttery yellow in autumn less formal pruning will allow the flowers to develop into edible hazelnuts which can be harvested in september and october hazels are naturally bushy at the base and respond well to clipping so can be maintained as a formal decid