Aesculus

The shrub-like red buckeye is a red-flowered relative of the more familiar Balkan horsechestnut (A. hippocastanum), native to the ”deep south” of the United States. Although as a small tree it would be extremely useful in densely urban areas it has not been used much. Instead, the cross between the two species, the red horsechestnut (A x carnea), is widely used in both Europe and North America.

The red buckeye varies greatly in both habit and flower colour, the deep red attracting humming-birds to feed on their nectar in the wild.

Although the species is from a very different climate, the specimen planted at Mustila at the Festival Area has proved hardy and even flowered. Many of the species belonging to the horsechestnut family have shown themselves adaptable to a wide range of climates, and the success of this small southern tree seems added confirmation.

Native to the eastern United States, yellow buckeye grows naturally south of the Great Lakes. It is considered extremely hardy and is grown well north of its native range. The species is related to the more familiar European horse chestnut (A. hippocastanum) which is fairly common in parts of Finland, but the American species is planted much more rarely.

Yellow buckeye has decorative shiny palmately compound leaves, smaller and more slender than the horse chestnut’s. In autumn they turn yellow, orange or scarlet. The tree flowers in June with erect panicles of cream or yellowish blossoms. The capsule is smooth, very unlike the spiky cover of the horse chestnut.

At Mustila there is a large old yellow buckeye hidden away in the grove that lies between Atsalearinne (Azalea slope) and Viinitupa (Wine Cellar). Younger trees have been planted on Azalea slope in recent years, using selected seedlings from Mustila’s own seed collecting expeditions as well as seed from commercial collectors.

Yellow buckeye is closely related to Ohio buckeye (A. glabra) and they hybridise easily in the wild. The Mustila trees might well include such hybrids (A. x marylandica).

The horse chestnut is a handsome flowering tree which can be grown in favourable spots in the south of Finland. When young, it is tender to autumn frosts and winter damage, which is why plants are usually imported from elsewhere. Hardiness improves with age. 

The horse chestnut can best be described in a single word: big! In temperate climates it can achieve heights up to 30m. In Finland it only achieves about half this size, but develops a broad crown. Branches are sturdy and in winter have impressively large, sticky buds. In spring they produce large finger-lobed leaves and showy white flowers. In autumn the fruit is a large shiny brown nut covered in a spiky shell. The nuts are not edible by humans, but squirrels eat them.

At Arboretum Mustila the Balkan horse chestnuts have not grown as well as its American relatives, and there is not a single large specimen. The Arboretum collects seeds from Kouvola from a group of exceptionally large and hardy trees.