Persicaria amphibia

Tracheophyta MagnoliopsidaPolygonaceaePersicariaPersicaria amphibia


A floating aquatic perennial herb, which sometimes grows in considerable quantity in lakes, ponds, canals, slow-flowing rivers and ditches, or a terrestrial plant found in damp places on watersides, in marshes, wet meadows and dune-slacks, and as a weed of cultivated land. Reproduction is by seed and fragments of rhizome; terrestrial plants are much less floriferous than aquatic ones. 0-570 m (Blind Tarn, Westmorland).



World Distribution

Circumpolar Boreo-temperate element; widely naturalised outside its native range.

© P. Shannon

Broad Habitats

Light (Ellenberg): 7

Moisture (Ellenberg): 10

Reaction (Ellenberg): 6

Nitrogen (Ellenberg): 6

Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 3.7

July Mean Temperature (Celsius): 14.9

Annual Precipitation (mm): 986

Height (cm): 60

Length: 200

Perennation - primary


Life Form - primary

Perennial hydrophyte (perennial water plant)

Life Form - secondary


Comment on Life Form

genuinely intermediate; basic behaviour is as a rhizomatous hemicryptophyte



Clonality - primary

Rhizome far-creeping

Clonality - secondary

Irregularly fragmenting (mainly water plants)

Count of 10km squares in Great Britain: 2013

Count of 10km squares in Ireland: 644

Count of 10km squares in the Channel Isles: 11

Atlas Change Index: 0.27

Weighted Changed Factor: 0

Weighted Change Factor Confidence (90%)


JNCC Designations


Atlas text references

Atlas (174c)
Grime JP, Hodgson JG, Hunt R
1988.  Comparative Plant Ecology.
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1979)
Lousley JE, Kent DH
1981.  Docks and knotweeds of the British Isles. Botanical Society of the British Isles Handbook no. 3.
Meusel H, Jäger E, Weinert E
1965.  Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
Preston CD, Croft JM
1997.  Aquatic plants in Britain and Ireland.