Irish wildflowers BSBI map

Japanese Knotweed, Reynoutria japonica, Glúineach bhiorach
Photographs: Co. Cork

Japanese Knotweed
Reynoutria japonica (Fallopia japonica)
Glúineach bhiorach
Family: Polygonaceae

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

Spikes of white flowers. Reddish zig-zag stems. Broad leaves, oval-triangular, pointed. Spreads rapidly by rhizomes, forms large thickets. Height: To 2m

Roadsides, wasteland, streamsides. Widespread and very invasive introduction, difficult to eradicate. Originally introduced as garden plant, now designated as a significant invasive plant in Ireland

Similar: Giant Knotweed, Reynoutria sachalinensis

Japanese Knotweed, Reynoutria japonica, Glúineach bhiorach

Japanese Knotweed, Reynoutria japonica, Glúineach bhiorach
Japanese Knotweed, Reynoutria japonica (Fallopia japonica), Glúineach bhiorach

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