A dioecious annual of disturbed waste places, cultivated ground, particularly in allotments and gardens, rubbish tips, walls, and roadsides, thriving on light, nutrient-rich soils. It produces a long-lived seed bank. Lowland.
M. annua is known from archaeological deposits in Viking York. It has spread from ports and town gardens, and comparison of the current map with that in the 1962 Atlas suggests that is still increasing.
As an archaeophyte M. annua has a Submediterranean-Subatlantic distribution.
Light (Ellenberg): 7
Moisture (Ellenberg): 5
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 7
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4
July Mean Temperature (Celsius): 16
Annual Precipitation (mm): 779
Height (cm): 50
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 793
Count of 10km squares in Ireland: 55
Count of 10km squares in the Channel Isles: 14
Atlas Change Index: 0.28
Weighted Changed Factor: 34
Weighted Change Factor Confidence (90%)
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
1995. Biological evidence from Anglo-Scandinavian deposits at 16-22 Coppergate. The Archaeology of York. 14:435-797+i-xxiii.
1978. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 2. 2 vols.