Bistorta affinis 'Darjeeling Red'

RHS Plant Profile

knotweed 'Darjeeling Red'

Synonyms

Persicaria affinis 'Darjeeling Red'
Polygonum affine 'Darjeeling Red'

Alpine Rockery Herbaceous Perennial

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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

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained or Poorly–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: South–facing or East–facing or North–facing or West–facing
Exposure: Exposed or Sheltered
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): H7

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Polygonaceae
Native to GB/Ireland: No
Foliage: Semi evergreen
Habit: Matforming
Genus: A genus of herbaceous, rhizomatous perennials with erect, unbranched stems, bearing short terminal spikes of small, white or pink, bell-shaped flowers
Name Status: Accepted

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 See https://www.rhs.org.uk/plants/trials-awards

Propagation

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

Suggested planting locations and garden types

City and courtyard gardens
Coastal
Cottage and informal garden
Gravel garden
Patio and container plants
Rock garden
Garden edging
Flower borders and beds
Ground cover

Pruning

No pruning required but remove spent flowers if necessary and comb out old leaves

Pests

Generally pest-free

Diseases

Generally disease-free