• 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

Corydalis cava

holewort

  • Other common names holewort
    hollow leek

    hollow root
    hollow wort

    see more
  • Synonyms Corydalis bulbosa misapplied
    Fumaria cava

  • Family Papaveraceae

  • Genus Corydalis can be annuals, biennials or tuberous or rhizomatous perennials, with ternately or pinnately lobed leaves and racemes of spurred, tubular flowers

  • Details C. cava is a tuberous perennial to 20cm in height, with ternately divided leaves and, in early spring, terminal racemes of white or purple flowers 2.5cm in length

  • Plant range C Europe

Characteristics

  • Foliage Deciduous

  • 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)

    H5

Colour

Sunlight

  • Partial Shade

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

  • Exposure Exposed or Sheltered

Soil

  • Chalk

    Chalk

  • Clay

    Clay

  • Sand

    Sand

  • Loam

    Loam

  • MoistureMoist but well-drained

  • SoilChalk, Clay, Sand, Loam

  • pHAcid, Alkaline, Neutral

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, humus-rich soil

Propagation Propagate by seed sown in containers in an open frame when ripe or by division in autumn

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

How to care

Pruning No pruning required

Pests Generally pest free

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

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.