Also known as Cultivated Knotweed · Cultivated Koenigia · Garden Knotweed
Himalayan knotweed (Koenigia polystachya) is a vigorous, upright perennial herb native to the Himalayas, known for its dense clusters of small white flowers and potential
At-a-glance light, water, soil, and growing conditions from plant data
Full sun to partial shade
75% intensity
Prefers full sun for best flowering, but tolerates partial shade.
Consistent moisture
50% intensity
Keep soil evenly moist, but not waterlogged. Reduce in winter.
Loam, Clay, Sandy, Acidic, Neutral, Alkaline
50% intensity
Moderate
50% intensity
Hardy in temperate climates. Prefers cool to moderate temperatures.
Moderate
50% intensity
Feed annually with compost, and liquid fertilizer during growing season.
Safety information from plant toxicity data
| Attribute | Value |
|---|---|
| Toxic for humans | No 0/5 intensity |
| Toxic for pets | No 0/5 intensity |
| Edible | No |
None
Key traits and growing stats from plant data
Watering, pruning, propagation, and repotting details from plant data
Keep the soil consistently moist, especially during the growing season. Avoid waterlogged conditions. Water thoroughly when the top 2-3 cm of soil feels dry to the touch.
Reduce watering in winter, allowing the soil to dry out slightly between waterings.
Prune in late winter or early spring before new growth begins. Remove any dead, damaged, or weak stems. Cut back flowering stems from the previous year to encourage fresh growth and flowering.
Can be pruned hard to control size and shape.
Propagate from seed sown in autumn or early spring. Division of established clumps is best done in early spring. Cuttings can be taken from semi-ripe wood in summer, but are less reliable than seed or division.
Repot container-grown plants every 2-3 years in early spring. Choose a pot that is slightly larger than the current one. Use a good quality, well-draining potting mix. Ensure adequate drainage holes in the pot.
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Monthly activity intensity for bloom and fruit across both hemispheres.
Flowering & fruiting calendar
Flowering & fruiting calendar
Photos of Himalayan Knotweed (Koenigia polystachya)
Common names and botanical synonyms
Botanical classification
| Rank | Name |
|---|---|
| Kingdom | Plantae |
| Division | Tracheophyta |
| Class | Magnoliopsida |
| Order | Caryophyllales |
| Family | Polygonaceae |
| Genus | Koenigia |
| Species | Koenigia polystachya |
Similar in genus Koenigia
Answers based on plant encyclopedia data
