Artemisia tilesii is a tall aromatic herb in the aster family (Asteraceae), which occurs in gravel bars, meadows, and occasionally in tundra and rocky alpine situations. Artemisia tilesii also commonly occurs around ground squirrel colonies in Denali. Plants grow 15-80 cm tall from a tough rhizome. Most leaves are on the stem, large, 2-10 cm, green and glabrous above and gray and hairy to tomentose beneath. Leaves are pinnately divided into 3-5 lanceolate lobes with toothed margins. The inflorescence is spike-like with several nodding flower heads. The involucralbracts are green to white tomentose with a brown scarious margin. Only disc flowers are present in the small compact heads (5-8mm wide), with yellowish to pinkish corollas. Fruits are achenes. This species is easy to distinguish from other local Artemisia species by its large, broad stem leaves (as opposed to the finely divided leaves in other related species).
Artemisia tilesii flowers mid to late summer.
Artemisia tilesii is monoecious with bisexual flowers. Plants are likely wind pollinated, but its breeding system has not been studied. Seeds have a tuft of hairs to aid in wind dissemination.
Tall wormwood is an important medicinal plant throughout its range, notable for its strong aromatic smell. . The Dena'ina used it in poultices, teas, infusions and chews for colds, coughs, cuts, burns, pain and other ailments. Inupiat uses include poultices and teas for colds, cuts, infections, pain and rashes. The Yup'ik use this plant for a variety of internal and external ailments, including, colds, constipation, infection, and stomach problems. Tall wormwood is also widely used as a switch in steam baths. Tall wormwood leaves are also used to clean hands after cutting fish, to reduce the smell. For more detail, see Garibaldi 1999 and sources cited within, and Jernigan et al. 2015.
Artemisia tilesii is an amphi-Beringian species occurring in Siberia, throughout Alaska, across northern Canada to Northwest Territory and Quebec and south to the Pacific side of the continental divide in the Pacific Northwest. In Alaska, A. tilesii occurs is suitable habitat statewide, and is also widespread and common on both sides of the Alaska Range in Denali.
Artemisia tilesii occurs over a wide range of elevations in Denali National Park (134 m to over 1500 m) with an average site elevation of 751 m. This species is found over a large range of slopes (0 to 47 degrees).