• 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

Arisaema candidissimum

white-spathed jack in the pulpit

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
white-spathed jack in the pulpit

© RHS

  • Other common names white-spathed jack in the pulpit

  • Family Araceae

  • Genus Arisaema are mostly tuberous perennials usually with palmately lobed leaves, and distinctive tubular, hooded spathes within which the tiny true flowers are clustered at the base of the club-like or filamentous spadix, followed by a spike of red berries

  • Details A. candidissimum is a tuberous perennial to 30cm in height, with leaves composed of three ovate leaflets, appearing after the flowers. White, hooded spathes, striped pale pink, with a greenish tube are 10cm in length and appear in summer

  • Plant range W China

Characteristics

  • Foliage Deciduous

  • Habit Columnar/Upright

  • Toxicity Ingestion may cause severe discomfort

  • 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)

    H4

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Chalk

    Chalk

  • Sand

    Sand

  • MoistureMoist but well-drained

  • SoilLoam, Chalk, Sand

  • pHAcid, Neutral

Size

  • Ultimate height 0.1-0.5 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 5-10 years

How to grow

Cultivation Grow in moist but well-drained humus-rich soil in a cool site. In colder regions may need winter protection and tubers must not dry out when dormant

Propagation Propagate by seed, sowing them in containers in a cold frame in autumn or spring. Offsets may be removed in late summer

Suggested planting locations and garden types Flower borders and beds Underplanting of Roses and Shrubs Cottage & Informal Garden

How to care

Pruning No pruning required

Pests Susceptible to slugs and vine weevil

Diseases Generally disease free

Did you find the information you were looking for?

RHS members can get exclusive individual advice from the RHS Gardening Advice team.

Join the RHS now

Get involved

We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.