Koenigia × fennica 'Johanniswolke'
knotweed 'Johanniswolke'
A tall, clump-forming perennial to 2m with large, lance-shaped green leaves and strong, upright stems producing plumes of small, intensely fragrant, creamy-white flowers over a long period in summer, followed by pinkish-red seed heads. Suitable for the back of a flower border. Holds well without the need for staking
Synonyms
Persicaria × fennica 'Johanniswolke'Aconogonon 'Johanniswolke'
see morePersicaria polymorpha 'Johanniswolke'
Persicaria alpina misapplied
Koenigia alpina misapplied
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Size
Ultimate height
1.5–2.5 metresTime to ultimate height
2–5 yearsUltimate spread
1–1.5 metresGrowing conditions
Moisture
Moist but well–drained, Poorly–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Cream White | Green | Pink Red | |
| Autumn | Green | |||
| Winter |
Position
- Full sun
- Partial shade
Aspect
East–facing or North–facing or South–facing or West–facing
Exposure
Exposed or Sheltered Hardiness
H6Botanical details
- Family
- Polygonaceae
- Native to GB / Ireland
- No
- Foliage
- Deciduous
- Habit
- Clump forming
- Genus
A genus of annual or clump-forming perennial plants with terminal or axillary inflorescences carried on upright stems. Flowers are small, pale-coloured usually white or pink. Seeds are borne in achenes
- Name status
Accepted
How to grow
Cultivation
Grow in any moist soil in full sun or partial shade. Substantial mounds of foliage steadily increase in size, needing space and careful siting 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 or propagate by seed in spring
Suggested planting locations and garden types
- Architectural
- Cottage and informal garden
- Flower borders and beds
Pruning
No pruning required. Cut back after flowering
Pests
Generally pest-free
Diseases
Generally disease-free
Get involved
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