• 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

Iris ensata 'Alpine Majesty'

Japanese water iris 'Alpine Majesty'

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
Japanese water iris 'Alpine Majesty'

© RHS

  • Other common names Japanese water iris 'Alpine Majesty'

  • Family Iridaceae

  • Genus Iris may be rhizomatous or bulbous perennials, with narrow leaves and erect stems bearing flowers with 3 large spreading or pendent fall petals, alternating with 3 erect, often smaller, standard petals, in late winter, spring or early summer

  • Details 'Alpine Majesty' is a vigorous, rhizomatous, clump-forming compact perennial with grassy green upright foliage to 80cm high. Flowers are composed of white drooping standards with yellow-green signals wit typically three large flowers on a stem to 65cm high, flowering early to midsummer

Characteristics

  • Foliage Deciduous

  • Habit Bushy

  • Toxicity All parts may cause 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)

    H6

Colour

Sunlight

  • Partial Shade

  • Full Sun

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

  • Exposure Exposed or Sheltered

Soil

  • Loam

    Loam

  • Clay

    Clay

  • MoisturePoorly-drained, Moist but well-drained

  • SoilLoam, Clay

  • pHAcid, 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 Grow in moist to wet, deep, humus-rich, neutral to acid soil in sun or part shade; it thrives at the margins of ponds or streams

Propagation Propagate by dividing iris rhizomes from midsummer to early autumn

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

How to care

Pruning Remove any dying foliage in autumn, old flower stems can be cut down after flowering

Pests May be attacked by slugs and snails

Diseases Generally disease free but may be affected by some Iris diseases

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