After most plants are done blooming, aromatic aster begins to open its flowers across the North Dakota prairies. Specimens with flowers can usually be found until early October. The plant is widely distributed in the eastern United States and ranges west to Colorado and New Mexico, at elevations up to 7,000 ft.
Aromatic aster is a rhizomatous perennial up to 2 feet tall. Up to a dozen stems grow from the rootcrown. Leaves are narrow, slightly over an inch long, and do not strongly clasp the stem like the leaves of many other asters. Each stem is branched profusely on the upper half, and supports several dozen violet to pink (usually blue) rayed flower heads up to an inch wide. Fruits are achenes about 3/16 inch long, sporting yellowish-white bristles.
Asters are seemingly avoided by livestock, so more plants are commonly found where competition by other plants has been reduced by heavy or moderate grazing. Aromatic aster is sometimes grown as an ornamental on dry, stony soil, but has no other known economic uses.
This plant is, of course, a member of the sunflower family (Asteraceae). This is a major family (about 15,000 species worldwide and 200 in North Dakota) in which many flowers are grouped into heads. Two types of flowers are formed; central tubular disc flowers and flat outer ray flowers. Most of the color comes from the rays. Aster means "star" in Greek in reference to this arrangement. The specific epithet oblongifolius means "oblong-leaved" in botanical Latin. Aromatic aster was first described for science by the eminent English naturalist Thomas Nuttall (1786-1859) who had the opportunity to collect many new species of plants in the upper reaches of the Louisiana Purchase.