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 (Persicaria wallichii), Glúineach spíceach