Rhododendron luteum
Common Name: pontic azalea 
Type: Deciduous shrub
Family: Ericaceae
Native Range: Europe, Caucasus
Zone: 6 to 9
Height: 4.00 to 5.00 feet
Spread: 4.00 to 5.00 feet
Bloom Time: May
Bloom Description: Yellow
Sun: Part shade
Water: Medium
Maintenance: Medium
Suggested Use: Naturalize
Flower: Showy, Fragrant
Leaf: Good Fall
Attracts: Hummingbirds, Butterflies
Tolerate: Rabbit

Culture

Best grown in acidic, light, sandy, well-drained soils in part shade. Tolerates well-drained humusy loams. Prefers a sun dappled shade or high open part shade. Foliage may scorch in full sun unless soils are kept uniformly moist. Consistent moisture is best, but soils must drain well (doesn’t like “wet feet”). Poor drainage inevitably leads to root rot, therefore raised beds/plantings should be considered in heavy clay soils such as those present in much of the St. Louis area. Roots must never be allowed to dry out. Acidify soils prior to planting and thereafter as needed. This shrub should be planted in a location protected from strong winter winds in the St. Louis area. Shallow, fibrous root systems (do not cultivate around shrubs) will benefit from a good mulch (wood chips, bark or pine needles) for retention of moisture, stabilization of soil temperatures and winter protection. Clip off spent flower clusters immediately after bloom as practicable. Slowly naturalizes by root suckers.

Noteworthy Characteristics

Rhododendron luteum, commonly known as pontic azalea or honeysuckle azalea, is an upright spreading deciduous azalea that typically matures to 4-5' tall over the first 10 years, but may occasionally rise over time to as much as 9-12' tall. It is native to alpine meadows, forests and slopes in Eastern Europe (Poland and the Balkans) southern Russia and the Caucasus. It is the only azalea native to Europe. Linear oblong to oblanceolate leaves (to 5" long) are sparsely covered with stiff hairs. Leaves turn yellow, orange and red in fall. Sweetly fragrant funnel-shaped yellow flowers (2" across) bloom in May in dense clusters (7-17 flowers per cluster) on naked stems just prior to or at the same time as the emergence of the new leaves. Nectar of this plant is toxic (10,000 soldiers in the army of Xenophon reportedly became ill in 401 B.C. after eating honey made from the nectar of this plant in an area along the Black Sea coast of Turkey). This plant has frequently been used in hybridization (one of the parents of the Ghent azaleas).

Genus name comes from the Greek words rhodo meaning rose and dendron meaning tree. Transferred from the Greek name for Nerium oleander.

Specific epithet means yellow in obvious reference to flower color.

Problems

Azaleas are susceptible to many insect and disease problems, including but not limited to canker, crown rot, root rot, leaf spot, rust, powdery mildew, aphids, borers, lacebugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips and whitefly. A healthy plant in the proper environment with proper care should have limited problems, however.

Garden Uses

Group or specimen for shrub borders, mixed borders, open woodland gardens, native plant gardens and open shade gardens. Effective near patios and as a specimen around the home.