• 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

Saxifraga callosa (8)

Limestone saxifrage

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
Limestone saxifrage

© � RHS 1985

  • Other common names Limestone saxifrage

  • Synonyms Saxifraga callosa lingulata
    Saxifraga lingulata

  • Genus Saxifraga can be annuals, biennials, evergreen or herbaceous perennials, mostly mat-forming in habit, with simple or palmately lobed leaves and starry or rounded flowers which may be solitary of in panicles or cymes

  • Family Saxifragaceae / Saxifragaceae

  • Species S. callosa is an evergreen perennial with rosettes of linear, lime-encrusted silvery-grey leaves to 8cm in length. Starry white flowers 1cm in width are carried in large open panicles on arching stems to 25cm

  • Plant range Europe

  • Horticultural Group Ligulatae section saxifrages are evergreen perennials forming monocarpic rosettes, usually clustered, of narrowly strap-shaped or oblong, lime-encrusted leaves, with sprays of small white, pale yellow or pink flowers in late spring or early summer

Characteristics

  • Foliage Evergreen

  • 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

    H5

Colour

Sunlight

  • Full Sun

  • Aspect South-facing or East-facing

  • Exposure Exposed

Soil

  • Chalk

    Chalk

  • MoistureWell-drained

  • SoilChalk

  • pHAlkaline

Size

  • Ultimate height

    0.1-0.5 metres

  • Ultimate spread

    0-0.1 metre

  • Time to ultimate height

    2-5 years

How to grow

Cultivation Grow in moderately fertile, very well-drained, alkaline soil in full sun. May be intolerant of winter wet, can be grown in a pot in an alpine house

Propagation Propagate by seed sown in pots in an open frame in autumn. Propagate by detaching rosettes and rooting as cuttings in late spring or early summer

Suggested planting locations and garden types Gravel Garden Patio & Container Plants Rock Garden

How to care

Pruning No pruning required

Pests Aphids, slugs, vine weevil and glasshouse red spider mite may be a problem

Diseases Generally disease free

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