• AGM plants

    AGM plants have been through a rigourous 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

Crocosmia masoniorum

Giant montbretia

AGM plants

AGM plants have been through a rigourous 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
Giant montbretia

© � RHS 1998

  • Other common names Giant montbretia

  • Genus Crocosmia are deciduous cormous perennials with erect, sword-shaped leaves and branched spikes of showy, funnel-shaped flowers in summer

  • Family Iridaceae / Iridaceae

  • Species C. masoniorum is a corm forming clumps of narrow leaves and branched sprays of upward-facing, brilliant orange-red flowers 5cm in length, on stems to 1.2m in height, from midsummer

  • Plant range S Africa

Characteristics

  • Foliage Deciduous

  • Habit Clump-forming

  • 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)
    Old hardiness ratings

    While we update our systems with the new hardiness ratings you may still see old hardiness ratings in your search results. These are denoted as 'Old'.

    • H1 - Requires heated glass
    • H2 - Requires unheated glass
    • H3 - Hardy outside in some regions of the UK
    • H4 - Hardy throughout the UK
    • H1 + H3 - Requires heated glass but may be grown outside in summer

    For full details of the hardiness ratings see

    see more

    H4

Colour

Sunlight

  • Partial Shade

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

  • Exposure Sheltered

Soil

  • Chalk

    Sand

  • Chalk

    Clay

  • Chalk

    Chalk

  • Chalk

    Loam

  • MoistureMoist but well-drained

  • SoilSand, Clay, Chalk, Loam

  • 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 Plant 8 to 10cm deep in moderately fertile, humus-rich soil. Lift and divide congested clumps to maintain vigour

Propagation Propagate by seed sown in containers in a cold frame as soon as ripe or by division in early spring as growth begins

Suggested planting locations and garden types Flower borders and beds Cut Flowers Low Maintenance Wall-side Borders City & Courtyard Gardens Cottage & Informal Garden Gravel Garden Mediterranean Climate Plants Prairie Planting

How to care

Pruning No pruning required

Pests Generally pest free

Diseases Generally disease free

Advertise here