Impatiens capensis


An annual, thoroughly naturalised by rivers, canals and adjacent reservoirs. The seeds can be ejected from its capsules to a distance of a few metres, and can be dispersed by water. Lowland.



World Distribution

Native of North America; also naturalised in France and Germany, although on a smaller scale than in our area.

Broad Habitats

Light (Ellenberg): 7

Moisture (Ellenberg): 9

Reaction (Ellenberg): 7

Nitrogen (Ellenberg): 6


Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 3.7

July Mean Temperature (Celsius): 16.2

Annual Precipitation (mm): 723

Life form information

Height (cm): 60

Perennation - primary


Life Form - primary

Therophyte (annual land plant)



Clonality - primary

Little or no vegetative spread

Distribution information

Count of 10km squares in Great Britain: 323

Count of 10km squares in Ireland: 1

Count of 10km squares in the Channel Isles: 0

Atlas Change Index: 0.71

Weighted Changed Factor: 36

Weighted Change Factor Confidence (90%)


Distribution information

JNCC Designations


External Species Accounts

PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.

Atlas text references

Atlas (96b) Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols,
Hultén, E., and Fries M.
, Königstein, (1986)
Vergleichende Chorologie der zentraleuropäischen Flora. Volume 2. 2 vols,
Meusel, H., Jäger E., Rauschert S., and Weinert E.
, Jena, (1978)
The distribution and dispersal of two alien species of Impatiens, waterway weeds in the British Isles,
Trewick, S., and Wade P. M.
, Proceedings EWRS / AAB 7th Symposium on Aquatic Weeds 1986, p.351-356, (1986)