Common wormwood, armoise absinthe

Perennials, 40–60(–100) cm (mat-forming), aromatic. Stems gray-green (sometimes woody proximally), densely canescent to glabrescent (hairs appressed). Leaves deciduous, gray-green; blades broadly ovate, 3–8 × 1–4 cm, mostly pinnately lobed (basal 2–3-pinnatifid, lobes obovate), faces densely canescent. Heads (nodding) in open (diffusely branched), paniculiform arrays 10–20(–35) × (2–)10–13(–15) cm. Involucres broadly ovoid, 2–3 × 3–5 mm. Phyllaries gray-green, densely sericeous. Florets: pistillate 9–20; bisexual 30–50; corollas 1–2 mm, glandular. Cypselae (± cylindric, slightly curved, obscurely nerved), ± 0.5 mm, glabrous (shiny). 2n = 18.

Flowering mid summer–fall. Widely cultivated, persisting from plantings, disturbed areas; 0–1000 m; introduced; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask.; Calif., Colo., Conn., Idaho, Ill., Ind ., Iowa, Kans., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., S.C., S.Dak., Tenn., Utah, Vt., Wash., Wis., Wyo.; Europe.

Artemisia absinthium provides the flavoring as well as the psychoactive ingredient for absinthe liquor, a beverage that is illegal in some markets. Known as a powerful neurotoxin, absinthe in large quantities is addictive as well as deadly. The species is popular in the horticultural trade. Prized by gardeners for its gracefully scalloped leaves and gray-green foliage, it creates an attractive and winter-hardy flower border.