• 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

Delphinium King Arthur Group

delphinium King Arthur Group

  • Other common names delphinium King Arthur Group

  • Synonyms Delphinium 'Pacific Giant King Arthur'

  • Family Ranunculaceae

  • Genus Delphinium can be annuals, biennials or perennials, with palmately lobed basal leaves and showy bowl-shaped flowers in spikes, racemes or panicles

  • Details King Arthur Group are erect perennials with large, semi-double, white-eyed, reddish-purple flowers in summer

Characteristics

  • Foliage Deciduous

  • Toxicity All parts may cause severe discomfort if ingested

  • 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)

    H5

Colour

Sunlight

  • Full Sun

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Chalk

    Chalk

  • Sand

    Sand

  • MoistureMoist but well-drained, Well-drained

  • SoilLoam, Chalk, Sand

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 1-1.5 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in a fertile, well-drained soil in full sun; shelter from strong winds and stake well. Apply a balanced liquid every couple of weeks in the growing season. For best flower spikes thin shoots when 7cm high to leave a minimum of 2-3 shoots on young plants and 5-7 shoots on established plants.

Propagation Propagate by seed sown at 13°C in early spring

Suggested planting locations and garden types Flower borders and beds Cut Flowers Cottage & Informal Garden

How to care

Pruning Deadhead by cutting spent flower spikes back to small flowering side shoots. Cut down all growth to ground level after it has withered in autumn.

Pests Prone to slugs, snails, leaf miners and caterpillars

Diseases May be affected by powdery mildews, crown rot and a virus

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