Comarum palustre (syn. Potentilla palustris), known by the common names purple marshlocks, swamp cinquefoil and marsh cinquefoil,<ref name=BSBI07>Template:Cite web</ref> is a common waterside shrub. It has a circumboreal distribution, occurring throughout North America, Europe, and Asia, particularly the northern regions. It is most commonly found on lake shores, marshy riversides and stream margins, often partly submerged with foliage floating. It is a parent of some Fragaria–Comarum hybrids, ornamental plants produced by crossing with strawberries.
Its branches spread into leaves with three to seven narrow leaflets which are sharply jagged. The stem is a reddish-brown, low sprawling, vine-like structure. Flowers extend from the branch which vary from red to purple, and are about one inch in diameter, blooming in summer. The stems roots at the base then rises to about Template:Convert.<ref>Parnell, J. and Curtis, T. 2012. Webb's An Irish Flora. Cork University Press.Template:ISBN</ref>
Swamp cinquefoil prefers peat soils but can also grow in moist sandy areas. It flourishes in USDA Zone 3 (minimum Template:Convert). It grows to about Template:Convert wide by Template:Convert high when cultivated properly.
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