Taxonomy

Musk thistle is a biennial plant. First year plants are less than two feet tall (forming a "rosette") and do not bloom. Second year plants grow up to six feet tall and produce a number of large flowers that mature in late June.

The leaves are hairless and dark green, with a conspicuous light green midrib. They often have silvery edges.

The stem is spiny and looks as if it has "wings" because the bases of the leaves grow downward and continue onto the stem.