Japanese pieris is an ornamental shrub that is attractive year-round. In late summer, the reddish flower buds for next year’s bloom appear. During the winter months, these bead-like buds are offset against the evergreen, glossy foliage.
Japanese pieris is an early bloomer; it blooms for about two weeks in late winter to early spring. The white or pink flowers resemble those of lily-of-the-valley but without a strong fragrance.
Because it is a slow grower with a dense, upright growth pattern, Japanese pieris is a good choice for foundations and shrub borders.
The leaves, flowers and secondary products (honey) of Japanese pieris is highly toxic to humans, pets, and other domestic animals. Like rhododendron, it contains grayanotoxins whose ingestion can be fatal. For this reason Japanese pieris is not recommended if children play in your yard, or family pets roam the yard.
|Botanical Name||Pieris japonica, Andromeda japonica|
|Common Name||Japanese pieris, Japanese andromeda, fetterbush, lily-of-the-valley bush|
|Mature Size||Nine to 12 feet height, four to eight feet width|
|Sun Exposure||Full sun to part shade|
|Soil Type||Sandy, silt, loamy|
|Soil pH||6 and above|
|Bloom Time||Late winter to early spring|
|Flower Color||White, pink|
|Native Area||Eastern China, Taiwan, Japan|
How to Grow Japanese Pieris
The mountain thickets where Japanese pieris originates provide the shrub with natural protection from strong winds. The shrub does best in locations that mimic this sheltered habitat.
Once the shrub is established, you won’t have much pruning to do because the way it grows naturally is attractive. The one thing you can do for a neater look is to remove the spent flowers right after the bloom.
Japanese pieris prefers full sun to partial shade. In warmer climate zones, it should be planted in a location where it is protected from the hot afternoon sun.
The soil should be rich in organic matter and moist but well-drained; Japanese pieris does not do well in wet soils.
Japanese pieris is an acid-loving plant that won’t tolerate alkaline soil. Before planting, check the soil pH and add a specialized fertilizer for azaleas, camellias, and rhododendron, which contains sulfur to increase the pH level.
In the absence of rain, Japanese pieris needs regular deep watering about once a week. Keep the soil moist to about three inches deep.
A layer of pine needle mulch, about two to three inches thick, helps retain soil moisture.
Temperature and Humidity
It is possible to plant Japanese pieris in zone 5 but you might lose flower buds during winter freeze.
Japanese andromeda is susceptible to different fungal diseases, which spread especially in humid weather. Therefore proper spacing—whether you plant more than one pieris, or other shrubs nearby—is crucial for good air circulation and plant health. Allow about six to seven feet between shrubs, and keep in mind their mature size.
Add a fertilizer for azaleas, camellias and rhododendron only in late winter and early summer, and follow the package instructions for the amount.
Varieties of Japanese Pieris
There are numerous cultivars of Japanese pieris that vary in hardiness, size, flower color, and bloom time.
The dwarf, compact cultivars are suitable to be grown in containers.
'Mountain Fire' is one of the most popular cultivars due to the show that new foliage puts on: it’s vibrant red-orange. The cultivar has a compact growth habit; it gets about four feet tall and three feet wide over the span of ten years.
Pieris japonica var. yakushimensis 'Cavatine' is a dwarf, compact cultivar that grows only about two to three feet tall and wide. It has an abundance of creamy-white, bell-shaped blossoms and blooms in April or May, thus later than the species.
'Valley Rose' is a compact, rounded cultivar with light pink flowers in late winter to early spring. It grows three to five feet tall and wide and is hardy in zones 6 to 8.
‘Dorothy Wyckoff’ is another compact, rounded, vigorously growing cultivar about five feet tall and wide at maturity, with deep red flower buds and pale pink flowers. It is especially recommended for container growing.
In terms of wildlife, Japanese pieris gets high ratings for deer-resistance.
The shrub can be affected by leaf spot and phytophthora root rot, both diseases caused by fungi. Root rot occurs especially in soil with poor drainage.