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Herbaceous Perennial

Persicaria affinis

lesser knotweed

P. affinis is a mat-forming herbaceous perennial about 25cm high with elliptic to lance-shaped dark green leaves, 5-15cm long, which turn red-bronze in autumn, and from midsummer to mid-autumn spikes 5-8cm long of flowers, each 5mm long, which open bright reddish pink, fade to pale pink, and then turn brown during winter; it is an excellent ground-cover plant

Other common names
East Indian knotweed
Synonyms
Polygonum affine
Bistorta affinis

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Size
Ultimate height
0.1–0.5 metres
Time to ultimate height
2–5 years
Ultimate spread
0.5–1 metres
Growing conditions
Chalk
Clay
Loam
Sand
Moisture
Moist but well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Pink Green
Autumn Pink Bronze Red Green
Winter Brown Bronze Red Green
Position
  • Full sun
  • Partial shade
Aspect

South–facing or North–facing or West–facing or East–facing

Exposure
Exposed or Sheltered
Hardiness
H7
Botanical details
Family
Polygonaceae
Native to the UK
No
Foliage
Evergreen
Habit
Matforming
Potentially harmful
May irritate skin, may cause mild stomach upset if eaten. Wear gloves and other protective equipment when handling
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

Name status

Correct

Plant range
Himalaya

How to grow

Cultivation

Grow in moist but well-drained soil in sun or partial shade

Propagation

Propagate by seed, sown in containers in a cold frame in spring, or by division in spring or autumn

Suggested planting locations and garden types
  • City and courtyard gardens
  • Cottage and informal garden
  • Low Maintenance
  • Flower borders and beds
  • Garden edging
  • Underplanting of roses and shrubs
  • Banks and slopes
  • Ground cover
Pruning

No pruning required

Pests

Generally pest-free

Diseases

Generally disease-free

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