Lindera obtusiloba Seeds | Japanese Spicebush
LATIN NAME: Lindera obtusiloba
COMMON NAME: Japanese Spicebush, Blunt-lobed Spicebush
Plant Profile
The lobing is not fixed. Shoots growing strongly, and the regrowth that appears after a stem is cut, produce conspicuously three-lobed leaves, while the leaves on slower, older wood are usually oval and undivided. This kind of variation within one plant, so that the leaf shape depends on the vigour of the shoot that carries it, is a real field character of the species and the reason the epithet refers to lobes that are blunt rather than pointed. The leaf margin is smooth and slightly waved, the surface is soft and blue-green beneath, and the twigs are a warm olive-brown.
Male and female flowers are borne on separate plants. The male flower carries nine fertile stamens in three whorls, and the inner whorl has a pair of small glands at the base of each filament, a detail that matters in identifying the genus. The female flower has a rounded ovary and a short style. Both sexes produce small umbels of greenish-yellow flowers on bare twigs in the first warm spell of spring, well before the leaves have opened, and insects coming out of winter work them hard.
The autumn display is the reason gardeners grow it. The foliage turns a clear, even golden yellow that holds for a long time, and on a female plant the small red drupes ripen against it, each fruit sitting in the shallow cup formed by the persistent flower base. Male plants give the better autumn colour, female plants give the fruit, and a pair is needed if seed is wanted. In eastern Asia the fruits are eaten by thrushes and bulbuls, which scatter the seed along hedgerows and woodland edges.
Japanese spicebush belongs at the edge of a wood or in a shrub border where the roots are cool, not in a formal bed. Its earliest flower is of real value to bees at a lean time of year, and the foliage feeds the caterpillars of several moths of the laurel group. The leaves are strongly enough scented that they have been used to scent stored clothing, the way a bay leaf is used in a larder.
Science & Biotechnology
The aromatic oil in the leaves and twigs is dominated by sesquiterpene hydrocarbons, with germacrene D and caryophyllene among the leading components and a smaller share of monoterpenes, which is what gives the crushed tissue its heavy, resinous warmth rather than the sharpness of a mint. The genus as a whole is studied for sesquiterpene lactones and for aporphine-type alkaloids, and extracts of the leaves and root bark have been examined for anti-inflammatory activity in the laboratory. The seed yields a fixed oil of the kind pressed from other laurels.
Uses & Benefits
Break a twig of Japanese spicebush between your fingers and the scent arrives before you have a name for it: part camphor, part warm pepper, the resinous smell of the laurel family concentrated into a shrub of only four or five metres. The leaves that carry that oil are the other surprise. On vigorous shoots they are often divided into three blunt lobes, so that a single branch looks as though it were hung with small green mittens. Both features belong to the same plant, and both are useful. Snap a leaf and there is no doubt which shrub you are standing in front of.
The name is shared with a plant from the other side of the world. The American spicebush has smooth oval leaves that are never lobed, and they smell of allspice when crushed, and it never produces the lobed foliage that makes the Japanese species so easy to spot. The two are separated by an ocean and by their chemistry as much as by their geography. The leaf shape of the parent plant is worth checking when buying seed.
Growing from Seed
Collect the drupes when the outer skin has softened, rub off the pulp and sow at once, because the oily seed loses its power to grow if it dries out. Sow about a centimetre deep in a lime-free mix of two parts leafmould, one part loam and one part coarse grit, and leave the pan in a cold frame outdoors for the winter. The thick cotyledons stay in the soil and the shoot appears with two or three true leaves; move each seedling into its own pot when the second true leaf has opened, taking care not to break the fleshy root. Named plants are also raised from softwood cuttings of a known sex, which is the only way to be certain of a female.
Water young plants through their first two summers and keep a leafmould mulch over the roots; dry ground in full sun will scorch the foliage at the edges. The shrub wants soil that stays cool and a position out of the worst wind, because late frost can catch the young leaves as they open. Very little pruning is needed: take out one or two crowded old stems after flowering and leave the rest. New plants can be started from a rooted layer, since low branches root where they touch the soil.
Under glass the shrub can carry soft scale on the young wood, and vine weevil grubs will hollow out the roots of a container plant, so inspect the pot in autumn. In the open, waterlogged soil is the main hazard, because the family is prone to root rot when the ground does not drain; raise the planting mound and add grit to heavy clay.
Our Take
Japanese spicebush is worth growing for the scent alone, and the golden autumn colour settles the argument. If you have room for a group, add the Chinese spicebush for its glossy evergreen foliage, and the red-fruited spicebush for a heavier crop of scarlet drupes. For a narrow space, the willow-leaved spicebush takes clipping well.
Related Reading
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