Bistorta affinis 'Superba'
knotweed 'Superba'
A semi-evergreen perennial forming a wide mat to 20cm in height, with dark green, elliptic leaves and erect spikes of small pale pink flowers that deepen to crimson with age
Synonyms
Bistorta affinis 'Dimity'Polygonum affine 'Superbum'
see morePersicaria affinis 'Dimity'
Polygonum affine 'Dimity'
Persicaria affinis 'Superba'
Size
Ultimate height
0.1–0.5 metresTime to ultimate height
5–10 yearsUltimate spread
0.5–1 metresGrowing conditions
Moisture
Moist but well–drained, Poorly–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Pink Red | Green | ||
| Autumn | Pink Red | Green Bronze | ||
| Winter | Green |
Position
- Full sun
- Partial shade
Aspect
South–facing or North–facing or West–facing or East–facing
Exposure
Exposed or Sheltered Hardiness
H7Botanical 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
Grow in any moist soil in full sun or partial shade See https://www.rhs.org.uk/plants/trials-awards for further information about RHS plant trials and awards
Propagation
Propagate by division in spring or autumn
Suggested planting locations and garden types
- Rock garden
- Cottage and informal garden
- Flower borders and beds
- Garden edging
- Ground cover
Pruning
Cut back after flowering
Pests
Generally pest-free
Diseases
Generally disease-free
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.