Pieris is peerless as an evergreen ornamental shrub

Pieris

Pieris japonica ‘Variegata’
Family: Ericaceae (Heath family)
Genus: Pieris
Species: japonica
Featured cultivar: ‘Variegata’

Picture courtesy of Oregon State University Landscape Plant Database

Pieris japonica is a lovely shrub by any name. Our gardening forebears referred to it as Japanese andromeda. One small person in my family calls it a moptop, which neatly describes its form. But the common name that seems most apt at this time of year is lily-of-the-valley shrub. Indeed, the individual bell-shaped flowers of P. japonica are similar to the waxy white blooms of the small woodland perennial that grows from a pip (Convallaria majalis). The fragrant flowers of Pieris japonica are borne in drooping clusters up to six-inches long, and range in color from icy white to a sumptuous rosy magenta, depending on the cultivar. The flower buds, which set in the fall, are attractive in their own right; and the flush of colorful new growth following spring bloom can be positively dramatic.

The Pieris genus has only seven species, all native to eastern Asia and the eastern United States. Three species and many hybrids are widely available in this country. Each is an evergreen and fully frost-hardy in our area, although P. japonica is the species mostly widely planted in the Northwest. Pieris japonica appreciates our climate and has long been a stalwart performer in home landscapes here, as specimens, hedges and participants in mixed borders. All species within the genus are characterized by similar flower form and simple leaves, glossy dark green in all but our featured cultivar, Pieris japonica ‘Variegata.’ Its pale green leaves are edged in a creamy white that takes on a pinkish glow in spring. Chinese pieris (Pieris forrestii) has six-inch leaves, by far the longest in the genus. The flowers of the mountain pieris (Pieris floribunda) are formed in upright rather than drooping clusters.

All types of Pieris bloom from February to April, and colorful new growth always comes on the heels of the long-lasting blossoms. It is not unusual, in fact, for the new growth to begin even before the blossoms fade. This is one of the most exciting features of Pieris, to home gardeners and hybridizers alike. This new growth can range from lime green to brilliant red, with every imaginable shade in between. There are many choices now available with beautiful combinations of bud and flower colors, and shades of new growth, that are quite extraordinary. Many of these are hybrids of P. japonica and P. forrestii, and several, including ‘Valley Valentine,’ were developed at Oregon State. Other named hybrids include ‘Forest Flame,’ ‘Valley Rose,’ ‘Valley Fire.’ ‘Temple Bells,’ and ‘Flamingo.’ Another, ‘Dorothy Wycoff,’ has foliage that bronzes in winter, as well as purplish red buds that open to deep red and white flowers.

Pieris japonica is a member of the same family as rhododendrons and azaleas, and it is both culturally and visually compatible with its cousins. It appreciates uniformly moist, acid soil rich with peat and other organic material. Good drainage is important. Give it the recommended application of fertilizer for acid-loving plants, in late January and again in early June, just before and just after flowering.

Place it in dappled shade, and make sure it is protected from drying winds and direct sunlight. It is perfect for a sheltered entryway or other visible spot where year-round good looks are important, and it is indispensable as part of a courtyard Asian garden.

Prune your Pieris just after the flowers fade, and use a light touch, removing little more than the spent blossoms. P. japonica has its own attractive shape, with upright, dense, tiered growth, so it doesn’t need to be kept in bounds. It is a very slow grower to perhaps 10 feet, although there are new, compact cultivars available. Some have a dwarf habit and never reach one foot in height. Unless you specifically choose the ‘Pygmaea’ or ‘Compacta,’ remember its eventual size when you place it; your Pieris will be a permanent garden feature. If it seems too small at planting time and you are disturbed by the empty space, surround it with shorter lived plants that can be removed in three to five years. You won’t want to mess with your Pieris once it is established. Another reason not to crowd it is its susceptibility to some fungal diseases. Good air circulation will help with management of these. Few pests bother Pieris here. In the eastern United States, lace bugs are a significant problem but they seem not to have arrived in Western Washington, yet.

Good gardening practices will go the longest way to insuring the health and long life of this wonderful shrub, one that landscape authority Donald Wyman has described “as beautiful an evergreen as it is possible to grow.