Pieris japonica Seeds | Japanese Pieris

Drooping clusters of white urn-shaped flowers and bronze new growth on Japanese pieris — Japanese Pieris (*Pieris japonica*): Ericaceae, Japan, China and Taiwan.

LATIN NAME: Pieris japonica

COMMON NAME: Japanese Pieris

Plant Profile

Japanese pieris is an evergreen shrub of two to four metres, with whorled, glossy, lance-shaped leaves that open bronze-red and mature dark green, and drooping clusters of small, urn-shaped white flowers in early spring. It is a plant of acid woodland in Japan, China and Taiwan, and it needs the same conditions as a rhododendron: lime-free soil, leaf mould, dappled shade and steady moisture. It is grown for the flowers and the new growth, and it is not a plant for the kitchen. The flower buds are formed in autumn and sit all winter in tight, beaded clusters at the shoot tips, which is a display in itself. The bark is grey-brown and smooth, and the shrub keeps a neat, rounded outline without clipping.

Science & Biotechnology

The genus is chemically defined by grayanotoxins, diterpenes that bind sodium channels and cause the classic poisoning syndrome of numbness, vomiting, slow heartbeat and low blood pressure. The same compounds are behind mad honey, the toxic honey made by bees foraging on rhododendrons and pieris, and there are documented poisonings from eating the flowers or drinking the nectar. The plant is also being studied for the andromedotoxin derivatives, and its phylogeny has been revised, with Pieris moved within the tribe Lyonieae. Its cultivars are mostly bud sports and seedlings selected for leaf colour. Its cultivar breeding is unusual in that most named forms are mutations rather than hybrids, which keeps the gene pool narrow.

Uses & Benefits

It is an ornamental shrub, full stop: a specimen for an acid border, a woodland garden or a large container, with cultivars selected for red new growth, variegated leaves and compact habit. The flowers are a good early nectar source for bumblebees, which are less affected by the toxins than vertebrates. It has no culinary or safe medicinal use, and the leaves, flowers and nectar should be kept away from children and from any home honey. The cut stems are also long-lasting in water, which makes it a useful florist’s material in spring. In Japan it is planted in temple gardens, where the early flowers are valued as a sign of the season.

Growing from Seed

Sow on the surface of a lime-free, humus-rich mix and do not cover, since the seed needs light; keep at eighteen to twenty-one degrees and expect germination in four to eight weeks. The seedling is slow and needs dappled shade. Grow it in ericaceous compost, water with rainwater, and plant out into acid soil with leaf mould. Prune after flowering if needed, and never let it dry out in summer, since bud set for the next spring depends on it. Sheltered shade suits it best, and lime in the soil will yellow it within a season.

Our Take

A beautiful acid-soil shrub with a dark side, and one to admire rather than to taste. Give it peat-free leaf mould, rainwater and shade, and keep the secateurs away in spring.

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