Mature Plant

Description: Plumeless thistle reproduces only by seed and grows most often as a biennial; however, it can occasionally grow as a winter annual or annual. During the first year of growth, a large basal rosette with a large tap root is formed. During the second year of growth, an erect flowering stem grows to a height of 3 to 6 feet. The stem is branched and has spiny wings. The leaves are alternate, narrow, deeply lobed, have scattered hair on the upper leaf surface, and dense white hair on the lower surface, especially along the midrib. Lobes on the leaves and stem, end in white to yellowish spines. The flower heads are globe-shaped, erect, single or loosely clustered, with spiny bracts at the base of each flower head. The flower heads are reddish-purple and 1/ 2 to 1 inch in diameter. Flowering occurs from June through August, with seeds maturing5 to 12 days after full bloom. The seeds are straw-colored with brown striations to the collar where the pappus is attached. The seeds are 1/16 inch in length, usually linear but occasionally curved.

Seedling

Distribution: Plumeless thistle is primarily found in pastures, waste areas, and along roadsides. It prefers sandy, well-drained soils. Plumeless thistle is found throughout Minnesota.