• 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

Aconitum 'Bressingham Spire'

monk's hood 'Bressingham Spire'

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
monk's hood 'Bressingham Spire'

© RHS

  • Other common names monk's hood 'Bressingham Spire'

  • Family Ranunculaceae

  • Genus Aconitum can be herbaceous perennials or biennials with lobed leaves and racemes or panicles of showy, hooded flowers

  • Details 'Bressingham Spire' is an herbaceous perennial to 90cm, with deeply divided, glossy dark green leaves and erect spikes of hooded, violet-blue flowers in late summer and autumn

Characteristics

  • Foliage Deciduous

  • Habit Bushy

  • Toxicity All parts are highly toxic if eaten

  • 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)

    H7

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Clay

    Clay

  • Chalk

    Chalk

  • Sand

    Sand

  • MoistureMoist but well-drained

  • SoilLoam, Clay, Chalk, Sand

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 0.5-1 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Best grown in moisture retentive, fertile well-drained soil in partial shade but will tolerate most soils and full sun. Staking may be necessary

Propagation Propagate by division in autumn or late winter to maintain vigour but plants may be slow to re-establish. Use protective gloves when handling any part of the plant

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

How to care

Pruning Cut down old flowering stems when flowering is finished

Pests Aphids may be a problem

Diseases Crown rot, Verticillium wilt, bacterial spotting of the foliage and powdery mildew may be problematic

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