• 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

Verbascum nigrum

dark mullein

  • Other common names dark mullein
    black-rooted mullein

    tall mullein

    see more
  • Family Scrophulariaceae

  • Genus Verbascum can be annuals, biennials, perennials or subshrubs mostly with hairy leaves and 5-petalled, saucer-shaped flowers

  • Details V. nigrum is an ornamental biennial or short-lived perennial. Its dark green leaves are hairy and make basal clumps out of which rise slender columns of warm yellow flowers with purple stamens at their centres. Flowering continues from early summer to early autumn

  • Plant range Europe, Asia

Characteristics

  • Foliage Semi-evergreen

  • Habit Columnar/Upright

  • 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)

    H6

Colour

Sunlight

  • Full Sun

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

  • Exposure Exposed or Sheltered

Soil

  • Loam

    Loam

  • Chalk

    Chalk

  • Clay

    Clay

  • Sand

    Sand

  • MoistureWell-drained

  • SoilLoam, Chalk, Clay, Sand

  • pHNeutral, Alkaline

Size

  • Ultimate height 0.5-1 metres

  • Ultimate spread 0.5-1 metres

  • Time to ultimate height 1-2 years

How to grow

Cultivation Usually found on calcareous, free-draining sites or disturbed ground. Mulleins are beneficial to wildlife as a pollen and nectar source when in flower, seeds are a food source for birds and in winter hollow stems act as a refuge for insects

Propagation Propagate by seed

Suggested planting locations and garden types Wildflower meadow Wildlife Gardens

How to care

Pruning None required

Pests May be attacked by mullein moth

Diseases Generally trouble 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.