Persicaria virginiana var. filiformis
thread-like Virginia knotweed
A clump-forming, deciduous herbaceous perennial to around 60cm with bright green foliage with burgundy-red 'V'-shaped markings. Upright red stems produce sprays of small red flowers in late summer. Seeds freely
Size
Ultimate height
0.5–1 metresTime to ultimate height
2–5 yearsUltimate spread
0.5–1 metresGrowing conditions
Moisture
Moist but well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green Red | |||
|---|---|---|---|---|
| Summer | Red | Green Red | ||
| Autumn | Red | Green Red | ||
| Winter |
Position
- Full sun
- Partial shade
Aspect
East–facing or North–facing or South–facing or West–facing
Exposure
Sheltered Hardiness
H6Botanical details
- Family
- Polygonaceae
- Native to GB / Ireland
- No
- Foliage
- Deciduous
- Habit
- Clump forming
- 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
How to grow
Cultivation
Grow in moisture-retentive but well-drained soil in full sun or partial shade
Propagation
Propagate by division in spring or autumn. Deadhead after flowering to avoid spread as seeds freely
Suggested planting locations and garden types
- City and courtyard gardens
- Cottage and informal garden
- Flower borders and beds
Pruning
No pruning required
Pests
Generally pest-free but may be susceptible to slugs and snails
Diseases
Generally disease-free
Get involved
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