• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases

Rhododendron occidentale (A)

western azalea

western azalea

© RHS

  • Other common names western azalea

  • Synonyms Azalea occidentalis

  • Family Ericaceae

  • Genus Rhododendron can be evergreen or deciduous shrubs or trees, with simple leaves, sometimes with a dense colourful indumentum of hairs on the lower side, and funnel-shaped, bell-shaped or tubular flowers that may be solitary or in short racemes

  • Horticultural Group Azaleas can be deciduous or evergreen, with mostly small, frequently fragrant, funnel-shaped flowers in spring or early summer; deciduous azaleas often have good autumn colour

  • Details R. occidentale is a bushy medium-sized shrub with glossy foliage turning orange and yellow in autumn. Fragrant, funnel-shaped flowers to 10cm in width are white or tinged with pink, and blotched yellow within

  • Plant range Western USA

Characteristics

  • Foliage Deciduous

  • Habit Bushy

  • Fragrance Flower

  • Hardiness

    Hardiness ratings

    All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

    • H1a - Under glass all year (>15C)
    • H1b - Can be grown outside in the summer (10 - 15)
    • H1c - Can be grown outside in the summer (5 - 10)
    • H2 - Tolerant of low temperatures, but not surviving being frozen (1 to 5)
    • H3 - Hardy in coastal and relatively mild parts of the UK (-5 to 1)
    • H4 - Hardy through most of the UK (-10 to -5)
    • H5 - Hardy in most places throughout the UK even in severe winters (-15 to -10)
    • H6 - Hardy in all of UK and northern Europe (-20 to -15)
    • H7 - Hardy in the severest European continental climates (< -20)

    H6

Colour

Sunlight

  • Partial Shade

  • Aspect South-facing or West-facing or East-facing

  • Exposure Sheltered

Soil

  • Sand

    Sand

  • Clay

    Clay

  • Loam

    Loam

  • MoistureMoist but well-drained

  • SoilSand, Clay, Loam

  • pHAcid

Size

  • Ultimate height 1.5-2.5 metres

  • Ultimate spread 1.5-2.5 metres

  • Time to ultimate height 10-20 years

How to grow

Cultivation Grow in moist but well-drained, leafy humus-rich, acid soil. Shallow planting is essential, deep planting will not be tolerated. Suitable for small gardens

Propagation Propagate by semi-hardwood cuttings

Suggested planting locations and garden types Flower borders and beds City & Courtyard Gardens Cottage & Informal Garden

How to care

Pruning Pruning group 17

Pests May be attacked by vine weevil, leafhoppers, lacebugs, scale insects, caterpillars and aphids

Diseases May be subject to powdery mildews, rhododendron petal blight, rhododendron bud blast and silver leaf

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