Cirsium palustre, the marsh thistle or European swamp thistle, is a herbaceous biennial (or often perennial) flowering plant in the daisy family, Asteraceae.Cirsium palustre is a tall thistle which reaches up to 2 metres (7 ft) in height. The strong stems have few branches and are covered in small spines. In its first year the plant grows as a dense rosette, at first with narrow, entire leaves with spiny, dark purple edges; later, larger leaves are lobed. In the subsequent years the plant grows ...