Japanese Horse Chestnut – Aesculus turbinata

Japanese Horse Chestnut – Aesculus turbinata
Family Hippocastanaceae – Horse-Chestnuts & Buckeyes.
Introduced to North America in the late 19th century, now widely planted as an ornamental or specimen tree.

In bloom on May 25th near Chicago; flower stalks (technically called a thryse) are a foot tall. This tree is 24 years old [1]
Japanese horse chestnut is a fast growing tree up to 30 m under ideal conditions. Introduced to China and North America, now widely planted as an ornamental and for timber [3].

The large leaves turn bright orange in autumn. Winter buds are red, glossy, and sticky. Leaves are compound and palmate, with 5 to 7 obovate, stalkless, toothed leaflets all attached at the same point at a central leaf stalk. [2]

Japanese Horse Chestnut Flowers
Creamy-white "candlestick" of flowers

Flowers are creamy-white with a red blotch, and are borne on an upright thyrse up to a foot tall in late spring. The fruit is a nearly spineless, egg-shaped yellow-green husk with usually 1 brown seed inside [3]. A truly spectacular specimen tree, suitable for formal gardens or wide lawns, Japanese horse-chestnut is tolerant of a wide range of soils.

Palmate leaflets to 16 inches long; seeds, horse-chestnuts below
conkers (seeds, horse-chestnuts)

1. Japanese Horse-Chestnut, Morton Arboretum accession 555-83-1, photos by Bruce Marlin
2. John White and David F. More, The Illustrated Encyclopedia of Trees – Timber Press
3. Flora of China, Aesculus turbinata
Family Hippocastanaceae – Horse-Chestnuts & Buckeyes
Consisting of three genra a 15 species, this small family is sometimes lumped together with Aceraceae (maple) in family Sapindaceae. Many are native to Europe, Asia, and North, Central, and South America. By far the most familiar of this family (at least in America) is the Ohio Buckeye (Aesculus glabra).
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