Rhododendron albiflorum

Common Names

White Rhododendron, White-Flowered Rhododendron, Cascade Azalea

Summary

White-flowered rhododendron is a western North American native shrub in the Ericaceae that grows as a rhizomatous, deciduous shrub up to about 2.5 m tall, forming dense thickets with erect stems and leaves that are narrowly elliptic to obovate, 2–9 cm long, often crinkled and sparsely hairy. Flowers are white, bowl-shaped, in leaf axils along the previous year’s growth, typically 1–4 per cluster, and very fragrant with a vanilla/jasmine-like scent, blooming in late spring to summer; its native range extends from British Columbia to northern Oregon and into Alberta, Montana, and Colorado, in moist conifer forests, alpine thickets, stream banks, and seeps on rock outcrops at elevations around 800–3500 m.

Culture and uses: it is very cold-hardy to about -30°C when dormant, with late frosts able to damage new growth and flowers, and it tolerates sun to shade but prefers woodland shade; soil should be humus-rich, lime-free, and well-drained with pH 4.5–5.5. Propagation can be achieved by seed, layering, or cuttings, and it is occasionally grown as an ornamental; all parts contain grayanotoxin, presenting potential toxicity to humans, and nectar honey may also be toxic.

Lifecycle

Perennial

Height

5 feet - 8 feet 2 inches

Spread

Unknown

Hardiness Zones

Zones 4

Sunlight Requirements

Ideally full sun to partial shade.

Soil Type

Peaty or well-drained sandy loam, acidic pH 4.5–5.5, lime-free, humus-rich.

Soil Drainage

Well-drained

Soil pH

4.5-5.5, Acidic

Bloom Color

White to creamy white, occasionally with yellow markings.

Bloom Time

Summer

Foliage Color

Green (upper surface light green; below dull green)

Fall Foliage Color

Brilliant reddish orange.

Leaf Lifecycle

Deciduous

Growth Rate

0.3 ft/year (about 3 ft in 10 years)

Seasons of Interest

Spring and Summer

Propagation Methods

Seeds, Layering, Cuttings

Attracts Wildlife

Bees: Yes