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Rhododendron /ro.doˈdɛn.drɔn/

Common name: Azalea

Rhododendron is a large genus of flowering shrubs and small trees in the heath family, Ericaceae, which includes the plants commonly called azaleas. They produce showy clusters of funnel- or bell-shaped flowers in spring and are native to temperate regions across the Northern Hemisphere. Most species are evergreen or deciduous shrubs that prefer cool, moist, acidic conditions.

Care summary

Sun Partial shade to dappled sun
Water Keep evenly moist; do not let dry out
Soil Acidic (pH 4.5–6), humus-rich, well-draining
Hardiness Zones 4–8 (varies by species)
Mature height 0.5–6 m (2–20 ft), by species
Pet safe Toxic to cats and dogs

Fun facts

  • All parts of rhododendrons contain grayanotoxins, making the plants — and even honey made from their nectar — poisonous.
  • The genus name comes from Greek words meaning 'rose tree'.
  • The Rhododendron is the national flower of Nepal and the state flower of West Virginia and Washington.

Common problems

    • Test soil and lower pH
    • Feed with ericaceous fertilizer
    • Mulch with pine needles or bark
    • Plant in raised beds or mounds
    • Improve drainage before planting
    • Avoid overwatering established shrubs
    • Hose undersides of leaves
    • Apply insecticidal soap when active
    • Keep plants well watered
    • Plant away from harsh winds
    • Water deeply before ground freezes
    • Use burlap screen in winter