Aesculus x glaucescens

And here is the Aesculus x glaucescens (synonym Aesculus x neglecta), a very rare hybrid horse chestnut in cultivation. It is a medium-sized tree, known for its pale yellow spring flowering, but especially for its finely cut foliage that becomes fiery in autumn. Like other American ornamental horse chestnuts, it is not too bulky, rather disease-resistant, remarkably colourful, and perfectly cold-hardy.

The Aesculus x glaucescens is a very ancient natural hybrid resulting from the cross-breeding between the very compact Aesculus sylvatica, native to the Appalachian forests of the USA, and the large Aesculus flava, a native tree of the eastern United States. This moderately-sized horse chestnut forms a trunk topped with a rounded and loose crown. At maturity, its dimensions reach 10 to 15 m in height and 5 to 10 m in width. Its branches bear smooth, slightly sticky buds. The leaves are digitate, composed of 5 leaflets, attached to the branch by short petioles. The leaflets are oblong-ovate, long-pointed, measuring up to 15 cm long. The young spring shoots are brownish, unfolding into light green leaves, then green, with a yellowish-green underside. In autumn, they gradually turn red. The nectariferous flowering takes place in May, more or less early depending on the climate. The very small flowers are pale yellow, veined with red at the base of the petals. They are grouped in fairly loose inflorescences, 10 to 15 cm long. It blooms in the second half of May. The fruits are smooth and brown, measuring 2 to 3 cm in diameter. Each one contains a seed. The trunk of this small tree is covered with smooth, brown bark.

Aesculus x neglecta thrives in deep, moist soil, preferably non-calcareous, in sunny or semi-shaded positions. It can be used as a standalone tree in a medium-sized garden or on a large plot of land. It can also be integrated into a bed of large shrubs or small trees with flowering or autumn foliage. It forms a beautiful combination with a blue-flowered Hydrangea like the Hydrangea serrata Blue Bird, with the Parrotia persica, the Hydrangea quercifolia, the silverberry or the Cotinus Royal Purple for example.