Fraxinus excelsior

Fraxinus excelsior forms a tall, domed head of branches and is easily identified by its large green leaves divided into eight to 12 leaflets that turn yellow in autumn before falling. Bark is smooth and pale brown to grey, and conspicuous black buds are arranged opposite each other along the stems, most visible in winter. Through autumn, winged seeds are borne in clusters. These are designed to spin through the air and spread themselves widely, so if there's an ash tree in your area, watch out for self-sown seedlings and remove them as soon as possible. Ash is fast-growing and reaches much of its mature size in around 25 years.

However, Fraxinus excelsior is not a good planting choice currently, due to Ash Dieback Disease (Hymenoscyphus fraxineus). This has become widespread in many areas of the UK and poses a serious threat to ash trees. Symptoms include black lesions on stems, black blotches on leaves, and extensive dieback of shoots and branches. This disease only attacks plants in the Oleaceae family, which includes the garden shrubs Phillyrea and Chionanthus. Affected trees become unstable and usually need felling to avoid becoming a danger to life.