• 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

Echium pininana

giant viper's bugloss

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
giant viper's bugloss

© RHS

  • Other common names giant viper's bugloss
    tower of jewels

  • Synonyms Echium pinnifolium

  • Family Boraginaceae

  • Genus Echium can be annuals, biennials, evergreen perennials or shrubs, with simple, coarsely hairy leaves and funnel-shaped flowers borne in panicles or dense spikes in summer

  • Details E. pininana is a rosette-forming biennial or short-lived perennial with lance-shaped, roughly silver-hairy leaves to 7cm long. Each rosette produces a flower panicle up to 4m long of funnel-shaped blue flowers with large bracts in mid and late summer

  • Plant range Canary Is

Characteristics

  • Foliage Evergreen

  • Habit Columnar/Upright

  • Toxicity All parts may cause stomach upset if ingested

  • 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)

    H3

Colour

Sunlight

  • Full Sun

  • Aspect South-facing or West-facing

  • Exposure Sheltered

Soil

  • Sand

    Sand

  • Chalk

    Chalk

  • Loam

    Loam

  • MoistureWell-drained

  • SoilSand, Chalk, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 2.5-4 metres

  • Ultimate spread 0.5-1 metres

  • Time to ultimate height 1-2 years

How to grow

Cultivation Under glass, grow in a loam-based potting compost (JI No3) in full light. Water freely when in growth, sparingly in winter. Outdoors, grow in moderately fertile, well-drained soil in full sun. Protect from winter frost in situ with horticultural fleece

Propagation Propagate by seed sown at 13-16°C in summer, overwintering seedlings at 5-7°C

Suggested planting locations and garden types Flower borders and beds Wall-side Borders City & Courtyard Gardens Coastal Cottage & Informal Garden

How to care

Pruning No pruning required

Pests Outdoors slugs may be a problem; indoors glasshouse whitefly and glasshouse red spider mite can be troublesome; vine weevils may also be found

Diseases Generally disease free

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