Mature Plant

Description: Musk thistle (also called nodding 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 with spiny leaves extending down the stern to give it a winged appearance The wings are lobed and wavy with each lobe ending in a spine. The leaves are dark bluish-green with light green midribs and have a white margin. The leaves are alternate, smooth, coarsely lobed, with 3 to 5 points per lobe, and are slightly wavy. Each lobe ends in a prominent white or yellow spine. The leaves have little or no hair on either surface. The flower heads are large, frequently as much as 2 inches across, on the ends of long spineless stems, and frequently droop. The flowers are deep rose to violet or purple and surrounded by large spiny bracts. Flowering occurs from late June through August and the seed matures in July through September. The seeds are a glossy yellowish-brown, oblong, 3/16 inch long, with a protrusion where they were attached to the pappus.

Seedling

Distribution: Musk thistle if primarily found in pastures, waste areas, and along roadsides. It prefers moist, alluvial soils but can be found on many different soil types. Musk thistle is found throughout southern Minnesota, with the most severe infestations in southeastem Minnesota.