A perennial herb growing on barish muddy ground near the sea, along the upper edges of saltmarshes, on sea walls and amongst coastal rocks; also in saline areas inland, and as a colonist by salt-treated roads. It favours compacted, poorly-drained, heavy soils. Lowland, with a roadside record at 520 m at Holme Moss (Cheshire).
As in the 1962 Atlas, this map includes records for subsp. distans and subsp. borealis; the latter is also mapped separately. Whilst its coastal distribution is stable (apart from being much better recorded in N. Scotland), it has spread rapidly along roadsides since 1970.
Eurosiberian Boreo-temperate element; widely naturalised outside its native range.
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Light (Ellenberg): 8
Moisture (Ellenberg): 8
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 7
Salt Tolerance (Ellenberg): 4
January Mean Temperature (Celsius): 4.1
July Mean Temperature (Celsius): 14.9
Annual Precipitation (mm): 859
Height (cm): 60
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 405
Count of 10km squares in Ireland: 39
Count of 10km squares in the Channel Isles: 2
Atlas Change Index: 3.02
Weighted Changed Factor: 74
Weighted Change Factor Confidence (90%)
Atlas text references
1994. 'Maritime' plants of roads in Cambridgeshire (v.c. 29). Nature in Cambridgeshire. 36:37-60.
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
1985. The updated distribution of maritime species on British roadsides. Watsonia. 15:381-386.
1982. De-icing salt and the invasion of road verges by maritime plants. Watsonia. 14:41-52.