Acer serrulatum Seeds | Serrulate Maple
LATIN NAME: Acer serrulatum
COMMON NAME: Serrulate Maple
Plant Profile
Serrulate maple is an endemic maple of Taiwan, growing ten to twenty metres in the cool, moist forests of the island’s central mountains. It has smooth grey bark, five- to seven-lobed leaves with finely serrated edges and a long, drawn-out central lobe, and small yellow-green flowers in spring. The samaras ripen in autumn and spin down in pairs. What makes the tree worth planting is the autumn colour: the leaves turn through yellow to a deep, saturated red, and in good years a whole hillside is scarlet for a fortnight. It grows at a thousand to two thousand metres, in cloud forest where the air is damp and the soil is acid, and it is one of the trees that give the Taiwanese mountains their autumn reputation. It is closely related to the Japanese maples and is treated by some botanists as part of that group.
Science & Biotechnology
Acer serrulatum sits in the section Palmata of the genus, the group that contains the Japanese maples, and its relationship to Acer palmatum and Acer rubescens has been argued over for a century. Some treatments place it as a subspecies of A. rubescens, others keep it as a distinct species on the basis of leaf serration and fruit shape, and molecular work has not fully settled the question. The taxonomic uncertainty matters for conservation, because a plant that is not a species cannot be listed as one. The Taiwanese populations are geographically isolated and show low genetic diversity, which suggests a long history of small population size. The autumn colour comes from anthocyanins produced as chlorophyll breaks down, and the intensity depends on cool nights and bright days in autumn.
Uses & Benefits
The tree is grown as an ornamental in temperate gardens for its autumn colour and its elegant habit, and it is a good substitute for Japanese maples in cooler, wetter climates. It is also used in bonsai, where its fine branching and small leaves suit the technique. In Taiwan it is planted in mountain parks and along forest roads for its autumn display. The wood is hard and pale and used for small turnery. It has no medicinal use. As a garden tree it needs shelter from wind, which tears the leaves, and it prefers a site with moist soil and dappled shade, though it will take full sun where the ground stays cool.
Growing from Seed
Collect the samaras in autumn and sow them fresh, or stratify them in damp sand at four degrees for three months. Sow one centimetre deep in a leafy, free-draining mix and keep at fifteen to eighteen degrees; germination takes one to three months and is often uneven. The seedlings are slow and should be kept in half shade for their first two years. Grow on in deep pots, since the roots resent disturbance. Plant out in autumn into moist, acid, well-drained soil in dappled shade, and mulch with leaf mould. Protect from late frost, which damages young growth, and from wind. Prune only to remove crossing branches in winter.
Our Take
A Taiwanese maple with scarlet autumn colour and a taxonomic argument attached to it. Give it damp, acid soil and shelter from wind.
Related Reading
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