Species Native to Missouri
Common Name: roseshell azalea
Type: Deciduous shrub
Family: Ericaceae
Native Range: Central and eastern United States
Zone: 3 to 8
Height: 4.00 to 8.00 feet
Spread: 4.00 to 8.00 feet
Bloom Time: April to May
Bloom Description: Pink
Sun: Part shade
Water: Medium
Maintenance: Medium
Flower: Showy, Fragrant
Attracts: Hummingbirds, Butterflies
Tolerate: Rabbit
Culture
Best grown in rich, humusy, acidic, medium moisture, well-drained soil in part shade. Organically rich, moisture-retentive soils that drain well are the key. Poor drainage can cause root rot, and raised plantings should be considered in heavy clay soils. Shallow roots must never be allowed to dry out and appreciate a good organic mulch (e.g., bark, oak leaf or pine needle) to retain moisture and stabilize soil temperatures. Pruning is usually not necessary.
Noteworthy Characteristics
Rhododendron prinophyllum, commonly called early azalea or roseshell azalea, is a deciduous azalea native to Missouri. It typically occurs on wooded, north-facing slopes and wooded ravines and along streams in the far southeastern part of the State. Pink flowers appear in early spring (April-May in St. Louis) before or at the time of the emergence of the foliage. Flowers (to 1.5" long) are in trusses of 5-9 flowers each and have a pleasant, clove-like fragrance. Bright green foliage (grayish woolly beneath) turns bronzish in fall. Extremely winter hardy (grows in the wild as far north as Quebec) and is one of the parents of the Northern Lights hybrids developed by the University of Minnesota. An upright, rounded shrub which typically grows 4-8' tall (less frequently to 15' tall) and as wide. Formerly known as Rhododendron roseum.
Genus name comes from the Greek words rhodo meaning rose and dendron meaning tree. Transferred from the Greek name for Nerium oleander.
Problems
Susceptible to an impressive list of potential diseases and insect predators, including but not limited to powdery mildew, blights, root rots, leaf spots, galls, aphids, borers, lacebugs, scale, leafhoppers, mealy bugs, thrips, whiteflies and mites. A healthy plant in the proper environment in good soil with proper care should have limited problems, however.
Uses
Specimen, mass or group. Woodland gardens, shrub or mixed borders, native plant gardens or foundation plantings.