Japanese knotweed
Reynoutria japonica Houtt.
Reynoutria japonica, synonyms Fallopia japonica and Polygonum cuspidatum, is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae.
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Japanese knotweedJapanese knotweed
Japanese knotweed
Japanese knotweed
Japanese knotweed
Japanese knotweed
Japanese knotweedJapanese knotweedJapanese knotweedOverview
Reynoutria japonica, synonyms Fallopia japonica and Polygonum cuspidatum, is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae. Common names include Japanese knotweed and Asian knotweed. It is native to East Asia in Japan, China and Korea.
Updated by lebachungtdh@gmail.com · 10/15/2026
In North America and Europe, the species has successfully established itself in numerous habitats; it is classified as a pest and invasive species in several countries. The plant is popular with beekeepers and its young stems are edible, making it an increasingly popular foraged vegetable with a flavour described as lemony rhubarb.
Updated by lebachungtdh@gmail.com · 10/15/2026
Các loài có quan hệ gần với cây cốt khí là Fallopia sachalinensis ở đông bắc châu Á và Fallopia baldschuanica ở Trung Á.
Updated by lebachungtdh@gmail.com · 10/15/2026
Củ cốt khí chứa hoạt chất emodin, có tác dụng nhuận tràng.
Updated by lebachungtdh@gmail.com · 10/15/2026
Life cycle
From seed to productRhizome planting
One- to two-year-old **rhizomes** are cut into 2–3-bud setts, treated against rot and planted where drainage is good.
Sprouting
The rhizome roots down and shoots push through the soil; the plant begins photosynthesising and storing reserves.
Growth & flowering
In season the plant opens **creamy-white flower panicles, July–September**, adding colour and nectar for insects.
New rhizomes & harvest
After a full growing season the plant retreats to its storage organ; **rhizomes dug in autumn–winter**.
Uses
- Củ cốt khí chứa hoạt chất emodin, có tác dụng nhuận tràng.
Habitat & conservation
It is native to East Asia in Japan, China and Korea.
Conservation
Japanese knotweed has not been assessed by the IUCN Red List (NE). As a medicinal plant, it benefits from sustainable collection and propagation to protect wild genetic resources.
References
- 1Wikipedia – Reynoutria japonica — Wikipedia,
- 2Kew POWO – Reynoutria japonica — Plants of the World Online (Kew),
- 3Wikidata – Q18421053 — Wikidata,