• 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

Clematis 'Ken Donson' (EL)

clematis 'Ken Donson'

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
clematis 'Ken Donson'

© RHS

  • Other common names clematis 'Ken Donson'

  • Family Ranunculaceae

  • Genus Clematis can be deciduous or evergreen shrubs or herbaceous perennials, mostly climbing by twining leaf-stalks, and often with showy flowers. Some have attractive fluffy seedheads in autumn

  • Horticultural Group Early Large-flowered clematis have large star-shaped flowers in early summer, often with a second flowering in late summer

  • Details 'Ken Donson' grows to 2.5-3m, and has large, deep blue flowers with contrasting white filaments and bright yellow anthers making up the gold stamens. Flowers may be produced any time between June and September and followed by prominent seedheads

Characteristics

  • Foliage Deciduous

  • Habit Climbing

  • 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 Sun

  • Partial Shade

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Clay

    Clay

  • Sand

    Sand

  • MoistureMoist but well-drained

  • SoilLoam, Clay, Sand

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 2.5-4 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Plant in a moisture-retentive, well-drained soil, with the roots and base of the plant kept cool and shaded by other plants or a layer of pebbles at the base. Plant with the crown 5-8cm deep to encourage new shoots to grow from below ground level

Propagation Propagate by softwood cuttings in spring, semi-ripe cuttings in summer or propagate by layering in late winter or early spring

Suggested planting locations and garden types Flower borders and beds Wall-side Borders City & Courtyard Gardens Cottage & Informal Garden Patio & Container Plants

How to care

Pruning Clematis pruning: group two

Pests aphids and slugs may be troublesome

Diseases Clematis wilt is an occasional problem

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