Irish wildflowers BSBI map

Himalayan Knotweed, Koenigia polystachya, Glúineach spíceach
Photographs: Reenaree, Co. Cork

Himalayan Knotweed
Koenigia polystachya (Persicaria wallichii)
Glúineach spíceach
Family: Polygonaceae

Flowering: August-September. Perennial. Introduced. Garden escape.

Loose panicles of white or pinkish-white flowers. The leaves are narrow-ovate to lanceolate and sometimes hairy on the underside. Forms thickets spreading by underground rhizomes and can be invasive. Height to 1.5m

Increasingly found on roadsides, river banks and waste ground.

Similar: Giant Knotweed, Reynoutria sachalinensis (previously Fallopia sachalinensis). Grows to 3m tall with greenish-white flowers.

Himalayan Knotweed, Koenigia polystachya, Glúineach spíceach

Himalayan Knotweed, Koenigia polystachya, Glúineach spíceach
Himalayan Knotweed, Koenigia polystachya (Persicaria wallichii), Glúineach spíceach

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