Acer circinatum Seeds | Vine Maple
LATIN NAME: Acer circinatum
COMMON NAME: Vine Maple
Plant Profile
Vine maple is a maple that behaves like a shrub, and in the deep shade of an old conifer forest it behaves like a vine. It grows three to eight metres tall, usually multi-stemmed, with long, slender, arching branches that lean out and down, and where those branches touch the ground they root and send up new shoots, so that a single plant can spread into a thicket several metres across. The bark is smooth and greenish when young and becomes grey and slightly rough with age.
The leaves are almost circular in outline, six to twelve centimetres across, divided into seven to nine shallow lobes with toothed edges, bright green above and paler beneath, and they turn a brilliant scarlet and orange in autumn, one of the best displays of any maple. The flowers open with the leaves in spring, in small drooping clusters with reddish sepals and white petals, and they are followed by samaras with wings that spread almost flat, nearly in a straight line. The species is native to the Pacific Northwest, from British Columbia south through Washington and Oregon to northern California, where it grows in the understorey of Douglas fir, hemlock and cedar forest, often along streams and in moist ravines.
Science & Biotechnology
The plant’s most studied feature is its biomechanics. The long, flexible stems bend under snow without breaking and spring back when the load melts, a property that lets the species survive in the heavy snow country of the Cascades, and measurements of stem stiffness, wood density and fibre angle have been used to model how understorey plants cope with mechanical stress. The same flexibility allows the branches to root where they touch the ground, producing clonal patches that can persist in deep shade where seedling establishment is rare. Studies of the understorey flora have shown that these patches are important for soil stability and for the diversity of the forest floor.
The species is also a useful subject in the study of shade tolerance. Seedlings survive for years under a closed canopy with very little light, growing slowly and responding quickly when a gap opens, and the physiology of that response, including the adjustment of leaf area, chlorophyll content and photosynthetic capacity, has been measured in the field. The seed has a deep dormancy that combines an impermeable seed coat with an immature embryo, and germination in the wild is spread over two springs, a pattern that spreads the risk of failure in a short, cool growing season. Work on the genus has used the species in phylogenetic studies of the maples, where it sits in a small group of western North American species.
Uses & Benefits
In the garden vine maple is grown for its autumn colour, its graceful arching habit and its tolerance of shade, and it is one of the best small trees for the north side of a house or for a woodland garden. It is also effective as a ground cover on a slope, where its layered stems will spread and hold the soil, and it can be trained as a single-stemmed specimen with careful pruning when young. It is a good plant for a Japanese-style garden, where its horizontal lines and scarlet autumn colour fit the idiom.
The wood is hard and fine-grained and has been used for small implements and for fuel, and the long, flexible stems were used by Indigenous peoples of the Pacific Northwest for basketry, fish traps and the frames of snowshoes. The species is also valuable for wildlife: the seed feeds small mammals and birds, and the foliage supports a range of invertebrates. It is not a timber tree and has no medicinal use of consequence, but it is one of the most ornamental of the North American maples.
Growing from Seed
The seed has a hard coat and an immature embryo, so it needs a warm, moist period followed by cold. Sow fresh seed in autumn in a pot of loam, leaf mould and grit, and leave it outdoors through two winters, or give three months at twenty degrees followed by three months at four degrees. Germination is erratic and often spread over two seasons. Scarifying the coat before sowing improves the result.
Prick the seedlings out into deep pots, since the root grows fast, and grow them on in a shaded frame for the first year, moving them into more light in the second. Plant out in autumn into moist, humus-rich, well-drained soil, in part shade or in sun where the soil stays moist. Mulch with leaf mould and water through the first two summers. The plant is hardy to about minus twenty-five degrees. Prune in late winter if a single trunk is wanted, removing the competing stems while the tree is young.
Our Take
A maple for shade and for autumn, with a habit that suits a woodland garden better than a border. Give it moist, acid soil and some shade, and it will colour the garden in October.
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