• 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

Osmunda regalis 'Cristata'

Royal fern 'Cristata'

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
Royal fern 'Cristata'

© � RHS

  • Other common names Royal fern 'Cristata'

  • Genus Osmunda are medium-sized to large deciduous ferns, usually from wet places, with erect or arching, pinnate or bipinnate fronds, bearing spores either on modified pinnae or on separate, smaller fronds

  • Family Osmundaceae / Osmundaceae

  • Species 'Cristata' is a robust deciduous fern, slowly forming a massive clump, with fronds bipinnately divided, the fronds, pinnae and pinnules forked or crested at the tips; fertile fronds are tipped with rusty-brown spore-bearing segments in summer

Characteristics

  • Foliage Deciduous

  • Habit Bushy

  • 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

    H6

Colour

Sunlight

  • Full Sun

  • Full Shade

  • Partial Shade

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

  • Exposure Exposed or Sheltered

Soil

  • Chalk

    Clay

  • Chalk

    Loam

  • Chalk

    Chalk

  • MoisturePoorly-drained, Moist but well-drained

  • SoilClay, Loam, Chalk

  • pHAcid, Neutral, Alkaline

Size

  • Ultimate height

    1-1.5 metres

  • Ultimate spread

    1-1.5 metres

  • Time to ultimate height

    5-10 years

How to grow

Cultivation Easy to grow in most cool, moist, lightly shaded sites and will grow in full sun if given plenty of moisture. Will tolerate alkaline soils if plenty of fibrous compost is incorporated. Useful for very wet sites

Propagation Propagate by division in early spring or autumn

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

How to care

Pruning Dead or damaged fronds may be removed as necessary

Pests Generally pest free outdoors

Diseases Generally disease free outdoors

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