Early spring finds the lily-of-the-valley bush (Pieris japonica), also called Japanese pieris, bearing drooping clusters of tiny, white urn-shaped blossoms. With growing requirements similar to the North Carolina native mountain andromeda (Pieris floribunda), Pieris japonica works well as a building foundation plant or growing alongside mountain laurels and azaleas. It is slow-growing and evergreen, eventually becoming 5 to 10 feet tall and wide. Japanese pieris grows in the warmer sections of USDA Plant Hardiness Zone 4 in western North Carolina, including the colder elevations of the Appalachians. Plant the shrub where it will not be exposed to harsh, cold and drying winter winds.
Select a location in your garden with moist, acidic soil that is rich in organic matter and freely drains. The soil should never be waterlogged after rain. Pieris japonica prefers a lightly or partially shaded spot, receiving no more than 4 to 6 hours of direct sunlight daily through tall tree branches. Avoid a windy location in the taller mountain areas.
Dig a planting hole twice as wide and just as deep as the Japanese pieris plant's root ball.
Remove the plant from its container and place it into the center of the planting hole, lining up the top of the root ball at the same level as the surrounding top edge of the hole. Back-fill the hole with soil, gently tamping it down with your hand as the hole fills. Create a small circular berm around the plant with excess soil to hold water when you irrigate the shrub. Do not pile soil atop the root ball; it should be even with the top of the hole and grade of the soil.
Sprinkle water from a can or bucket into the moat ring around the base of the Pieris japonica. Water the shrub daily for the first two weeks, adding at least 2 to 4 inches of water to the moat to keep the soil moist.
Place a 3 to 4-inch layer of organic mulch, such as pine needles or pine bark, over the root zone of the plant. Keep the mulch 2 inches away from the trunk.
Reduce watering to 2 inches every week from the third week after planting until the third month. After three months, reduce watering to only 1 inch each week.
Monitor the growth and health of the Japanese pieris, adding water to the root zone during droughts. Any dead or broken branches can be pruned away with a hand pruners any time of year, making the pruning cut 1/4-inch above a dormant bud or lower twig/branch junction.
Consider pruning errant branches or tip pruning only after the shrub completes blooming in mid-spring. In general, Pieris japonica grows with an attractive habit and doesn't require frequent pruning maintenance.