Rough blazing star is an upright perennial with an unbranched stalk. Flowerheads many, evenly spaced along a spikelike upper stalk, rose-purple. Involucral bracts (overlapping leaflike structures at the base of each flowerhead) rounded, somewhat spreading, appearing pouched or swollen, mostly with broad, thin, pale to transparent margins that look unevenly torn and are sometimes strongly purplish-tinged. Heads have 14–30 disk florets. Blooms August–November. Leaves alternate, the lowest to 15 inches long with a petiole, the upper ones much shorter, becoming sessile and narrowly lance-shaped. Rootstock a round corm.
Similar species: There are 9 species of Liatris recorded for Missouri, and many of these have been known to hybridize where they occur in the same vicinity. To distinguish between the various species and hybrids, one should be prepared to note details of the flower structure, such as the involucral bracts described above.