Japanese knotweed
Reynoutria japonica
Its underground rhizomes can extend up to 3 meters deep and 7 meters horizontally, capable of growing through asphalt, brick walls, and concrete foundations.
- Scientific name
- Reynoutria japonica
- Taxonomy
- Plantae › Tracheophyta › Magnoliopsida › Caryophyllales › Polygonaceae › Reynoutria
- IUCN Red List status
- Least Concern
- Population trend
- increasing
- Biome
- urban
- Habitat
- Riparian zones, roadside ditches, waste places, urban ruins, and railway embankments.
- Diet
- Autotrophic (photosynthetic)
- Range
- East Asia (native), North America (invasive), Europe (invasive)
- Size
- Stems grow 1 to 3 meters tall; rhizome networks can spread over 20 meters.
- Lifespan
- Perennial (individual clones can live for decades or centuries)
- Active
- diurnal
- Threats
- As an aggressive invader, it has few natural threats outside of targeted biological control agents, such as specialized psyllids, and intensive herbicide treatment.
- Safe to approach?
- Harmless to touch and non-toxic, but highly ecologically damaging. Do not cut, dig, or transport this plant yourself, as a fragment as small as a fingernail can regenerate into a new infestation. If found, report the location to local environmental authorities and consult professionals for eradication.
Reynoutria japonica , synonyms Fallopia japonica and Polygonum cuspidatum , is a large species of herbaceous perennial plant of the knotweed and buckwheat family Polygonaceae. It is commonly known as Asian knotweed or Japanese knotweed . It is native to East Asia in Japan, China and Korea. In North America and Europe, the species has successfully established itself in numerous habitats and is classified as an invasive species in several countries.
Photo: AnRo0002, no known copyright restrictions (public domain), PD, via iNaturalist
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