Originally an artificial hybrid between Horse Chestnut and Red Buckeye (Aesculus pavia), inheriting the former's form and foliage and the latter's flowers. Once sterile, it later evolved the ability to set fertile seed. First cultivated in 1818.

Quite widely planted in parks, large gardens and streets, and self-seeded in woodland edges and riverbanks. Uncommon elsewhere.

Monoecious. Insect-pollinated. Gravity-dispersed.

Medium (20m), with sinuous, often untidily weeping branches. Bark grey, smooth with lenticels, becoming scaly and, once over 30cm diameter, usually ugly with cankers. Twigs grey-brown; buds opposite, slightly resinous, terminal bud weak or absent. Leaves compound palmate, small and dark glossy with jaggedly serrate margins on very short leaflet stalks. Flowers dull crimson in short panicles (20cm). Fruit a globose, leathery, slightly prickly capsule (3-4cm) with glossy brown, pale-hilumed seeds. Horse Chestnut differs: larger, less crumpled leaflets, more resinous buds, pink flowers, spiky husks.

Most ornamental specimens are the cultivar ‘Briotii’, which has a more shapely, compact crown.

Its abundant nectar and pollen support bees and other pollinators.

This species is significantly unaffected by Horse Chestnut Leaf Miner (see Horse Chestnut p. xxx).

Ornamental.