• 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 ponticum

Pontica rhododendron

  • Other common names Pontica rhododendron

  • Synonyms Rhododendron × superponticum

  • 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

  • Details R. ponticum is a densely branched evergreen shrub with tough, leathery, dark green, oval leaves. Produces terminal trusses of 10 to 15 purple, funnel-shaped flowers in spring. Often used as a rootstock, surviving when the grafted variety has died

  • Plant range Europe Asia

Characteristics

  • Foliage Evergreen

  • Habit Bushy

  • 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

  • Full Shade

  • Full Sun

  • Partial Shade

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

  • Exposure Exposed or Sheltered

Soil

  • Clay

    Clay

  • Loam

    Loam

  • Sand

    Sand

  • MoistureMoist but well-drained

  • SoilClay, Loam, Sand

  • pHAcid

Size

  • Ultimate height 2.5-4 metres

  • Ultimate spread 2.5-4 metres

  • Time to ultimate height 10-20 years

How to grow

Cultivation This plant is listed on Schedule 9 of the UK Wildlife and Countryside Act as an invasive, non-native species. While this does not prevent it from being sold in the UK, or from being grown in gardens, the RHS encourages those that do grow it to take great care with managing it and with disposing of unwanted material. The RHS also encourages gardeners to find alternative plants to grow to those listed on Schedule 9. For suggested alternative plants see the Plantlife/RHS guide: Gardening without harmful invasive plants

Propagation Spreads naturally by seed and by layering

Suggested planting locations and garden types Hedging & Screens Banks and Slopes Low Maintenance Cottage & Informal Garden

How to care

Pruning Pruning group 8

Pests May be attacked by vine weevil, rhododendron leafhopper, pieris lacebug, scale insects, caterpillars and aphids

Diseases May be affected by various rhododendron diseases including powdery mildews, rhododendron petal blight, rhododendron bud blast, silver leaf and honey fungus

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