• AGM plants

    AGM plants have been through a rigourous 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

Persicaria affinis 'Darjeeling Red'

Knotweed 'Darjeeling Red'

AGM plants

AGM plants have been through a rigourous 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
Knotweed 'Darjeeling Red'

© � RHS

  • Other common names Knotweed 'Darjeeling Red'

  • Genus Persicaria can be annuals, herbaceous or evergreen perennials or sub-shrubs with simple leaves and small bell-shaped white or pink flowers in long-lasting spikes or panicles

  • Family Polygonaceae / Polygonaceae

  • Species 'Darjeeling Red' is a semi-evergreen perennial to 25cm tall, forming a mat of lance-shaped leaves to 15cm long, often becoming red in autumn; in summer dense spikes of small flowers open pink, becoming dark red when mature

Characteristics

  • Foliage Semi-evergreen

  • Habit Mat forming

  • Toxicity Contact with all parts may irritate skin

  • 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)
    Old hardiness ratings

    While we update our systems with the new hardiness ratings you may still see old hardiness ratings in your search results. These are denoted as 'Old'.

    • H1 - Requires heated glass
    • H2 - Requires unheated glass
    • H3 - Hardy outside in some regions of the UK
    • H4 - Hardy throughout the UK
    • H1 + H3 - Requires heated glass but may be grown outside in summer

    For full details of the hardiness ratings see

    see more

    H5

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Exposed or Sheltered

Soil

  • Chalk

    Clay

  • Chalk

    Loam

  • Chalk

    Sand

  • Chalk

    Chalk

  • MoistureMoist but well-drained, Poorly-drained, Well-drained

  • SoilClay, Loam, Sand, Chalk

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height

    0.1-0.5 metres

  • Ultimate spread

    0.1-0.5 metres

  • Time to ultimate height

    2-5 years

How to grow

Cultivation Prefers moisture retentive soil in sun or part shade but may spread quickly in wet soil. It is tolerant of dry and light soils in sun or shade where it will spread more gradually

Propagation Propagate by division in spring or autumn, or stem-tip cuttings of non flowering shoots

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

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