Pieris is a genus with seven species of shrubs in the Ericaceae, or blueberry, family. This plant genus is native to Japan, China, Taiwan, the east coast of North America, and Cuba. Pieris species are used mostly in landscaping and container gardening as ornamental plants. This is an easy-care group of plants that are not susceptible to diseases or many pests.
Members of this genus are also known as Japanese pieris, Japanese andromeda, lily of the valley, and fetterbush. They grow best in U.S. Department of Agriculture Hardiness Zones 4-8, which means that the lowest tolerable temperature is -30° Fahrenheit (-31° Celsius). In southern regions, Pieris does best in dappled shade, but in the northern regions it can be grown in full sun or partial shade. These plants prefer to grow in rich, well-drained soil with a pH level from very acidic to mildly alkaline. Soil should not become dried out, but should not be soggy either; both of these extremes will kill plants in this genus.
Species of Pieris range in height from 8 to 12 feet (2.4-3.7 m) tall and between 6 to 10 feet (1.8-3 m) wide. Bell-shaped, 1/4 to 2/3 inch (5-15 mm) long, white or pink flowers bloom in 6 inch clusters on the tips of the branches from summer until winter. The elliptical, 2 to 3 inch (5.0-7.6 cm) long foliage begins with a copper-red color, which gradually matures to a glossy green with serrated edges.
Pieris is a popular evergreen shrub with over 40 different cultivars used in landscaping. It works well along borders, hedges, or in a woodland garden. Many gardeners like to plant these species alongside rhododendrons and azaleas. Smaller species can be grown in containers, and the smallest species of Pieris is grown as a bonsai.
Members of this genus are resistant to most common plant diseases. They are, however, susceptible to a few different pests. Plants grown in full sun tend to become infested with lacebug or lacewing fly, mites, and nematodes. The larvae of the Lepidoptera species eats plants in this genus. Pests can be controlled with an insecticide made for rhododendron and azaleas. Pieris species do not usually need to be pruned; if pruning is necessary, it should be done very soon after the flowers fade.
Gardeners who decide to propagate Pieris species should take cuttings from greenwood tips in spring. If cuttings are not taken until summer, they should be from semi-hardwood. Plants in this genus are very slow to root. In order to encourage the growth of roots, warming the plant from the bottom may be necessary.