About
Rhododendron arborescens (A), smooth azalea, is a large, upright, deciduous shrub with glossy, mid-green leaves that turn red in autumn. In early summer, strongly scented, funnel-shaped, white to pink-flushed flowers with prominent red stamens are produced in abundance � one of the most fragrant of all azaleas.
About the genus
Rhododendron are evergreen or deciduous shrubs and trees with simple leaves and funnel-shaped, bell-shaped or tubular flowers � solitary or in short racemes � in a vast range of colours. They include azaleas and are essential shrubs for sheltered, moist, acid-soil woodland gardens.
Growing conditions
SunlightFull sun, Partial shade
Soil typeClay, Loam, Sand
Soil pHAcid
Soil moistureMoist but well-drained
AspectNorth-facing, West-facing, South-facing, East-facing
ExposureSheltered
UK hardinessH6
Plant details
Plant typeShrubs
HabitBushy
FoliageDeciduous
Height2.5-4 metres
Spread2.5-4 metres
Time to full height10-20 years
Suggested usesCoastal, Cottage and informal garden
Native toEastern N America
FragranceFlower
ToxicityHarmful if eaten. Wear gloves and other protective equipment when handling. Pets (dogs, cats, rabbits, tortoises) Harmful if eaten - for further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Care notes
CultivationSuitable for an open site but best grown in moist but well-drained, leafy, humus-rich acid soil in part shade with shelter; see rhododendron cultivation
PruningPruning group 1
PropagationPropagate by seed when ripe, or semi-ripe cuttings in late summer, layering in autumn or grafting in late summer or late winter
Pest resistanceMay be susceptible to vine weevil, rhododendron leafhopper, pieris lacebug, scale insects, caterpillars and aphids
Disease resistanceMay be susceptible to various Rhododendron diseases including powdery mildews, rhododendron petal blight, rhododendron bud blast, silver leaf and honey fungus