• 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

Sempervivum arachnoideum L. subsp. tomentosum (C.b. Lehm. & Schnittsp.) Schinz & Thell.

woolly cobweb houseleek

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
  • Other common names woolly cobweb houseleek

  • Synonyms Sempervivum arachnoideum 'Laggeri'
    Sempervivum webbianum

  • Family Crassulaceae

  • Genus Sempervivum are evergreen perennials forming mats of fleshy-leaved rosettes, often attractively coloured, with star-shaped pink or pale yellow flowers in summer

  • Details S. arachnoideum subsp. tomentosum is a mat-forming evergreen perennial with fleshy rosettes to 4cm in width, densely covered with cobwebby white hairs. Starry pink flowers 1.5cm in width are borne in flat cymes on stems to 15cm

  • Plant range Alps, Pyrenees

Characteristics

  • Foliage Evergreen

  • Habit Mat 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)

    H7

Colour

Sunlight

  • Full Sun

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Sand

    Sand

  • MoistureWell-drained

  • SoilLoam, Sand

  • pHNeutral, Alkaline, Acid

Size

  • Ultimate height Up to 10 cm

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in moderately fertile, humus-rich, moist but well-drained soil in full sun

Propagation Propagate by offsets

Suggested planting locations and garden types Flower borders and beds Garden Edging City & Courtyard Gardens Coastal Cottage & Informal Garden Gravel Garden Patio & Container Plants Rock Garden Wildlife Gardens

How to care

Pruning No pruning required

Pests Young growth may be attacked by slugs

Diseases Generally disease free

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