Trochodendron is a primitive tree species, the only living representative of the genus. The modest flowers resemble those of the Angelicas (Araliaceae) in early summer, while the leaves are leathery, evergreen, and toothed; they roll themselves up tightly in frost. The flowers are disc shaped, with groups of carpels joined at their edges into whorls. In its native rain forests in Japan and Taiwan, trochodendron can vary, sometimes growing into a large tree but also appearing as an epiphyte growing on the trunks of other trees.
Trochodendron has proved suprisingly winter hardy but is still such a newcomer to Finland that its mature size and the northern limits of its range here are still uncertain. However, it promises to be the first tree species (apart from the conifers) to survive Finnish winters while keeping its leaves. Trees of several metres can be found in Norway and Sweden which originated from the combined Scandinavian collecting expedition of 1976.
The young specimens planted in Mustila’s Alppiruusulaakso (Rhododendron Valley) are from the same 1976 seed. They have survived several winters without problems, at least those parts which have been snow-covered. But the above-snow parts have shown themselves to be extremely attractive to browsing hares.