Siebold’s maple is a beautiful small tree that grows in the mountain forests of Japan. The branches grow in layers, with dense, round, regularly lobed leaves which take on brilliant autumn colour before falling.
Siebold’s maple is reputed to be hardy even in Finland but closer examination reveals that almost all the plants growing under that name are in fact the closely related Korean maple, Acer pseudosieboldianum. This is also true at Mustila, whose only true Siebold’s maple was obtained only recently, and planted on Pähkinärinne (Hazelnut Slope)
Distinguishing between these two close relatives is extremely difficult. In western gardening literature the number of lobes, autumn colour, and angles of the samara wings are quoted, but they are all so variable that they cannot be used to distinguish the two. However, flower colour seems to be a reliable clue: the true Siebold’s flowers are pale yellow-green, but if there is also dark red present then this indicates that the specimen is Korean maple (Acer pseudosieboldianum), Shirasawa’s maple (Acer shirasawanum), or Japanese maple (Acer japonicum).