About
Rhododendron macrophyllum is an evergreen shrub, typically 2�4 m tall, with an upright branching habit and elliptic, dark-green leaves to 15 cm. In late spring it produces clusters of 20 or more bell-shaped flowers in shades of rose-pink to purple, occasionally white, with yellow-brown speckles on the upper petals. A bold and rewarding western American rhododendron for a sheltered, moist, acidic garden.
About the genus
Rhododendron, one of the largest and most diverse shrub genera, includes evergreen and deciduous species and hybrids ranging from dwarf alpines to large trees, all preferring moist, well-drained, acidic soil in sheltered positions with dappled shade or full sun.
Growing conditions
SunlightPartial shade
Soil typeClay, Loam, Sand
Soil pHAcid
Soil moistureMoist but well-drained
AspectNorth-facing, West-facing
ExposureSheltered
UK hardinessH6
Plant details
Plant typeShrubs
HabitColumnar upright, Spreading branched
FoliageEvergreen
Height2.5-4 metres
Spread2.5-4 metres
Time to full height5-10 years
Suggested usesCity and courtyard gardens, Cottage and informal garden
Native toUSA & Canada
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
CultivationGrow in moist but well-drained, humus rich, acidic soil, in partial or dappled shade. Choose a site away from frost pockets and sheltered from strong winds, and do not allow plants to dry out. Mulch annually, ideally with leaf mould. See rhododendron cultivation for more detailed advice
PruningMinimal pruning required, see pruning group 8 (evergreens)
PropagationPropagate by seed, by semi-ripe cuttings in late summer, or by layering in autumn
Pest resistanceMay be susceptible to vine weevil, rhododendron and azalea whitefly, rhododendron leafhopper, Pieris lacebug, scale insects, caterpillars and aphids
Disease resistanceMay be susceptible to powdery mildews, honey fungus, silver leaf and Phytophthora, as well as more specific Rhododendron diseases