• 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

Colchicum speciosum

Giant meadow saffron

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 meadow saffron

© � RHS 2002

  • Other common names Giant meadow saffron

  • Genus Colchicum are cormous perennials with usually coarse, broadly strap-shaped leaves which appear with or after the goblet-shaped flowers

  • Family Colchicaceae / Colchicaceae

  • Species C. speciosum is a corm producing 1-3 deep purplish-rose flowers up to 8cm in length, with pale green or whitish tubes. Strap-shaped, rich green leaves to 25cm in length develop in spring

  • Plant range N Turk., Iran, Cauc.

Characteristics

  • Foliage Deciduous

  • Habit Clump-forming

  • Toxicity All parts are highly toxic by ingestion

  • 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

    H5

Colour

Sunlight

  • Full Sun

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

  • Exposure Sheltered

Soil

  • Chalk

    Sand

  • Chalk

    Clay

  • Chalk

    Chalk

  • Chalk

    Loam

  • MoistureWell-drained, Moist but well-drained

  • SoilSand, Clay, Chalk, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height

    0.1-0.5 metres

  • Ultimate spread

    0.1-0.5 metres

  • Time to ultimate height

    2-5 years

How to grow

Cultivation May be naturalized in turf. Grow in moist but well-drained, deep, humus-rich, fertile soil. Intolerant of waterlogging

Propagation Propagate by seed sown in containers in an open frame when ripe or separate corms when dormant in summer

Suggested planting locations and garden types Flower borders and beds Low Maintenance Underplanting of Roses and Shrubs Cottage & Informal Garden Patio & Container Plants

How to care

Pruning No pruning required

Pests Slugs may be a problem

Diseases May be subject to bulb grey mould

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