Species Detail - Japanese Knotweed (Fallopia japonica) - Species information displayed is based on the dataset "Species Data from the National Vegetation Database".
Terrestrial Map - 10km
Terrestrial Map - 10km
Distribution of the number of records recorded within each 10km grid square (ITM).Marine Map - 50km
Marine Map - 50km
Distribution of the number of records recorded within each 50km grid square (WGS84)._0.jpg)
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Fallopia japonica
Japanese Knotweed
NHMSYS0000458716
RecommendedWell-formed
Fallopia japonica (Houtt.) Ronse Decraene, Fallopia japonica var. compacta (Hook.f.) J.Bailey, Fallopia japonica var. compacta (Hook. f.) J.P. Bailey, Fallopia japonica var. japonica (Houtt.) Ronse Decr., Fallopia japonica var. japonica (Houtt.) Decraene, Janapese Knotweed , Japanese Knotweed , Polygonum compactum Hook.f., Polygonum compactum Hook. f., Polygonum cuspidatum Siebold & Zucc., Polygonum cuspidatum Siebold. & Zucc., Reynoutria compactum Hook.f., Reynoutria japonica , Reynoutria japonica Houtt., Reynoutria japonica var. compacta (Hook. f.) Moldenke., Reynoutria japonica var. compacta (Hook.f.) Bucheim., Reynoutria japonica var. compacta (Hook.f.) Moldenke, Rumex obtusifolius var. transiens (Simonk.) Rech.f.
Invasive Species: EU Invasive Alien Species Regulation No. 1143/2014 || Invasive Species: Regulation S.I. 477/2011 (Ireland) || Invasive Species: High Risk Invasive Species (2013 Report) || Invasive Species: Regulation S.I. 374/2024 (Ireland) || Invasive Species: The Wildlife (Northern Ireland) Order 1985
fajap
(Houtt.) Ronse Decr.
Flowering plant
Species
54
49
35
01/08/2000
12/05/2010
2 January (recorded in 2018)
31 December (recorded in 2020)
Collated by the National Biodiversity Data Centre from different sources, Species Data from the National Vegetation Database, National Biodiversity Data Centre, Ireland, Japanese Knotweed (Fallopia japonica), accessed 31 August 2025, <https://maps.biodiversityireland.ie/Dataset/186/Species/41674>