Aesculus hippocastanum

Aesculus hippocastanum (horse chestnut tree or 'conker tree') is a large-growing deciduous tree with hard, rounded, shiny dark brown fruits, known as conkers. It has large, flat leaves up to 30cm long, made up of five to seven leaflets. Flowers are borne in late spring and early summer, in conical panicles made up of many small flowers which are white, fringed at the edges, and marked with pink. Once pollinated, the flowers develop fruit: roughly spherical spiny green cases, each containing one shiny brown conker. In winter, you can identify identify Aesculus hippocastanum by its smooth twigs and sticky, oval, dark red buds.

Its common name 'horse chestnut' could have arisen for several reasons. The fruits contain an anti-inflammatory substance called aescin and were once given to horses as a medicine. Another reason could be that the fallen leaves leave a horseshoe-shaped scar on the twig.

Aesculus hippocastanum grows up to 25m tall with a spread of up to 20m, and therefore isn’t suitable for gardens except large, woodland gardens. Over recent years, Aesculus hippocastanum trees in much of the UK have suffered from several pests and diseases, including horse chestnut scale, leaf miner, and canker.