Pieris is a genus of seven species of broad-leaved evergreen shrubs in the family Ericaceae, order Ericales. The genus is native to mountain regions of eastern and southern Asia — including Japan, China, Taiwan, the Himalayas, and Myanmar — as well as eastern North America and Cuba. In North America the plants are commonly known as andromedas or fetterbushes.
Plants grow 1–6 metres (3–20 ft) tall and 0.9–3.0 m wide. The leaves are spirally arranged, lanceolate-ovate, 2–10 cm long and 1.0–3.5 cm broad, with a leathery texture and entire or serrated margins. A distinctive ornamental feature is the young spring foliage, which emerges in vivid shades of red, bronze, or cream before maturing to dark green. The flowers are bell-shaped, 5–15 mm long, white or pink, sometimes with a honey scent, and borne in pendant racemes 5–12 cm long in mid-spring. The fruit is a woody capsule that splits into five sections to release numerous small seeds. Floral buds form in autumn and persist through winter, providing multi-season interest.
Pieris species are widely grown as ornamental garden shrubs, valued for their year-round display of winter buds, colourful new growth, and spring flowers. The common name "lily of the valley shrub" reflects the resemblance of the flowers to those of Convallaria, though the two genera are not closely related. Larvae of some Lepidoptera, including the engrailed moth, use Pieris as a food plant. Pieris floribunda has been noted as highly toxic.
Etymology
The genus name Pieris derives from Pieria, a region of ancient Greece regarded in Greek mythology as the home of the Muses.
Distribution
Pieris is native to mountain regions of eastern and southern Asia — including Japan, eastern China, Taiwan, the Himalaya, southwestern China (Yunnan), and northern Myanmar — as well as eastern North America and Cuba. Individual species occupy distinct ranges: P. japonica occurs in eastern China, Japan, and Taiwan; P. formosa across the Himalayas and southwestern China; P. floribunda and P. phillyreifolia in the eastern United States; and P. cubensis in western Cuba.
Ecology
Pieris species serve as larval food plants for some Lepidoptera, including the engrailed moth (Ectropis crepuscularia). The flowers produce nectar and may be strongly honey-scented, attracting pollinators in spring. Pieris floribunda has been documented as highly toxic, and the genus generally contains grayanotoxins that are harmful to livestock and humans.
Cultivation
Pieris shrubs are commonly grown as ornamental plants, prized for year-round interest: colourful red or bronze new growth in early spring, chains of small white flowers in mid-spring, and persistent buds through winter. Numerous cultivars have been selected for variation in spring foliage colour. They grow best in a partly shaded, sheltered position protected from drying winter winds, and strongly prefer acidic soil. An annual mulch of peat or composted pine needles is recommended to maintain soil conditions.
