Azalea
Azalea
Botanical name: Rhododendron
Bloom type: Perennial
Azaleas and rhododendrons are woody, evergreen or deciduous, rounded shrubs in the Ericaceae (blueberry) family. They are native to the United States and Asia and there are many cultivars and varieties, some native to North Carolina. They typically grow 6 to 10 feet tall and 5 to 8 feet wide. The genus name derives from the Greek words rhodo, which means rose, and dendron, meaning tree.
These plants prefer moist, well-drained, acidic soils in dappled shade and protection from afternoon sun which can scorch the leaves. They do not tolerate dense clay, so if you have clay soil, amend with organic material. The roots may rot if soil does not drain well. Plant the root ball high in the soil to help with drainage issues. Avoid overwatering and over-fertilizing. Pruning, if desired, may be done after flowering.
Azaleas and rhododendrons are at home as understory shrubs planted in groups in woodland or naturalized areas, or as specimens in pollinator gardens where the flowers will attract hummingbirds and the specialized bee Andrena cornelli. Some azaleas are offered as florist plants.
Per the American Rhododendron Society, "All azaleas are rhododendrons, but not all rhododendrons are azaleas." Here are some general characteristics to differentiate the two:
Quick ID Hints for Azaleas:
- Bloom in April
- Tubular or funnel-shaped flowers
- One flower per stem but has many stems that make the shrub look like it is covered in blooms
- 5 lobes per flower
- 5 stamens
- Multiple bloom colors including white, cream, pink, red, lavender, purple, orange, and yellow
- Foliage elliptical to obovate, thin, small, entire margins, thick pubescence, cluster at the tips of the branch, buds are smaller
- Most are deciduous but there are many evergreens
Quick ID Hints for Rhododendrons:
- Bloom later in the spring
- Bell-shaped flowers
- Blooms grow in clusters at the end of the branch
- 5 lobes per flower
- 10 stamens
- Blooms are typically white, pink, purple, red, and rarely yellow
- Leaves are green elliptic, entire margins, thick, leathery, glossy, undersides may be scaly or have small dots
- Terminal clusters of dried capsules release seeds
Insects, Diseases, and Other Plant Problems: Insect problems include aphids, borers, lace bugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips, and whitefly. Diseases include canker, crown rot, root rot, leaf spot, rust, and powdery mildew. This plant is frequently damaged by deer.
Information sourced from the NC Master Gardener Plant Toolbox
