Japanese Knotweed (Fallopia japonica) - Detail

Species Detail - Japanese Knotweed (Fallopia japonica) - Species information displayed is based on the dataset "National Invasive Species Database".

Terrestrial Map - 10km

Distribution of the number of records recorded within each 10km grid square (ITM).

Live Map

Marine Map - 50km

Distribution of the number of records recorded within each 50km grid square (WGS84).

Live Map

Species image

Scientific Name Fallopia japonica

Common Name Japanese Knotweed

Taxon Version Key NHMSYS0000458716 UnverifiedUnverified

Synonyms Fallopia japonica var. compacta (Hook. f.) J.P. Bailey, Fallopia japonica var. japonica (Houtt.) Ronse Decr., Polygonum compactum Hook. f., Polygonum compactum Hook.f., Polygonum cuspidatum Siebold & Zucc., Reynoutria japonica Houtt., Reynoutria japonica var. compacta (Hook. f.) Moldenke., Reynoutria japonica var. compacta (Hook.f.) Moldenke

Designations Invasive Species: Invasive Species || Invasive Species: Invasive Species >> High Impact Invasive Species || Invasive Species: Invasive Species >> Regulation S.I. 477 (Ireland)

Abbreviation fajap

Authority (Houtt.) Ronse Decr.

Group flowering plant

Rank Species

Number Of Records 4012

Number Of 10Km Squares 564

Number Of 50Km Squares 116

Oldest Record 19/08/1961

Newest Record 29/11/2024

Phenology - earliest record (across all datasets) 2 January (recorded in 2018)

Phenology - latest record (across all datasets) 31 December (recorded in 2020)

Species Profiles

Citation Collated by the National Biodiversity Data Centre from different sources, National Invasive Species Database, National Biodiversity Data Centre, Ireland, Japanese Knotweed (Fallopia japonica), accessed 21 April 2025, <https://maps.biodiversityireland.ie/Dataset/397/Species/41674>

Species Detail - Japanese Knotweed (Fallopia japonica) - Species information displayed is based on the dataset "National Invasive Species Database".

Terrestrial Map - 10km

Marine Map - 50km

Species image

Records per month (across all datasets)

Records per year (across all datasets)