Cirsium muticum (Swamp Thistle)

A high-value nectar plant, Cirsium muticum (Swamp Thistle) is a tall biennial producing a basal rosette of slightly prickly, deeply lobed leaves in the first year and flowers in the second year. Its slender upright stems are clad with alternate, deeply lobed, nearly spineless leaves, 10 in. long (25 cm), becoming gradually smaller as they ascend the stem. From mid-summer to fall, the plant boasts large, deep, rosy-purple, pincushion-like flower heads, 2 in. across (5 cm), packed with numerous disc florets. Blooming for about 6 weeks, they produce copious nectar and are visited by numerous native bees and butterflies. The ruby-throated hummingbird occasionally visits the blossoms for their nectar. This thistle also hosts the larvae of the Swamp Metalmark and Painted Lady butterflies, as well as a variety of moths, beetles, grasshoppers, and weevils.

The flowers give way to small seeds with tufts of white hair that facilitate dispersal by the wind. Songbirds eat the seeds and use the hair tufts of the seeds in the construction of their nests.

Found in swamps, wet woods, and thickets in the eastern half of the U.S. and Canada, Swamp Thistle has a stout taproot and does not spread by rhizomes. It is not invasive or as difficult to control as non-native thistles.

• Grows up to 2-7 ft. tall (60-210 cm). Swamp Thistle will die after flowering but will readily self-seed in the garden.
• Thrives in full sun in sandy, wet to moist soils. Tolerates partial sun and other soil types.
• Lovely in cottage gardens, naturalized areas, and prairies and meadows. Good as cut flowers, too!
• No serious pest or disease issues. Grazing animals will avoid grazing the immediate area around thistles.
• Native to much of the eastern half of the U.S. and Canada.