Norway maple grows mainly in central and eastern Europe, its range extending to the Crimea and Caucasus Mountains but not the British Isles. In Finland it is considered native, arriving after the last Ice Age. On the Finnish map there are numerous place names indicating where maples have grown of old. The northern limit of the species is the line Pori–Tampere–Kuopio–Joensuu; south of this it is the most commonly used deciduous hardwood in both gardens and parks.
The Norway maple is monoecious, i.e. all flowers are unisexual, having both male and female parts and it is one of only two deciduous hardwoods in Finland to be insect pollinated, the other being the common lime (Tilia cordata). Norway maple doesn’t produce root suckers, but spreads aggressively from seed. It flowers about the same time as the leaves appear, when the flowers cover the broad hemispherical crown in showy yellow-green. The red and yellow autumn colours are even more brilliant.
The positioning of the opposite leaves are a feature aimed at capturing the maximum amount of sunlight, though in youth the species also thrives in shade. When growing naturally, without excess nitrogen, Norway maple maintains its single trunk habit and makes a beautiful tree.
At Mustila there are old specimens on Ketunmäki (Fox Hill) dating back to the time before the Arboretum was founded. There are also large trees on Pähkinärinne (Hazelnut Slope) and Nikkarimäki (Nikkari Hill).
Norway maple sometimes suffers from black fungal spots on the leaves but they don’t really affect the tree. Pruning, if necessary, should be done in August to prevent sap ‘bleeding’. The leaf mould from this species does not improve the soil, unlike that of many other deciduous trees such as elm (Ulmus).