Artemisia vulgaris L. - Wormwood, Mugwort
Systematic position.Family Asteraceae, genus Artemisia L.
Biological group.This species is a tap-rooted perennial weed.
Morphology and biology.Rhizome is short and thickened in the upper part. Stem grows up to 160 cm tall and is straight, branchy, costate, usually brownish violet and slightly web-like pubescence. Leaves are deeply pinnatipartite or pinnatisect; deeply incised or dentate along the edges, lanceolate or linear-lanceolate lobes; green, glabrous or slightly web-like pubescence on the upper surface; grayish, densely tomentose underneath. Lower leaves are the largest and reach up to 15 cm in length, up to 11 cm in width. Bracteal leaves integral, linear. Lower ones are petiolar, the other leaves sessile. Inflorescence is calathidium, 3-4 mm long, 1.5-3 mm wide, oval, sessile, collected in dense racemes located on lateral secondary branchlets. Calathidial involucre has a web-like pubescence; its leaflets scarious along the edges; external leaflets scaphoid, with pointed tip; internal ones longer, elliptical. Receptacle is convex, glabrous. Marginal pistillate flowers with narrow, tubular, scarious tridentate corona; disk flowers bisexual; their corona narrow, cup-shaped conic, having five indentations above, reddish-brown. Fruit is achene, 1.2-2.0 x 0.3-0.5 x 0.3-0.4 mm, fusiform, slightly curved, elongate-oval, slightly convex on outer side, indistinctly dihedral on inner side, dark brown, glossy, often having five white longitudinal stripes, with light circular torulus at tip, with rounded rib at base. This plant blossoms in July and produces fruit in August. One plant can produce up to 15 thousand achenes, which sprout from a depth of no more than 3 cm. The minimum temperature for their germination is 2-4°C, the optimum is 22-24°C. In addition to reproducing by seeds, wormwood can propagate vegetatively by developing underground rhizomatous stalks.
Distribution.Europe, Asia Minor to India, China, Mongolia, Manchuria, Korea, Japan, Java, and North America. In the former USSR, it is distributed throughout the European part, in the Caucasus, Siberia, the Far East, and Central Asia.
Ecology.Wormwood grows among wastelands, along roads, near habitations, along river banks, on recent fallows, in gardens and kitchen gardens. It prefers carbonate, nutrient-rich, clay and sandy soils.
Economic significance.The plant grows among winter and summer grain crops, tilled cultures and perennial grasses. This species is an almost ineradicable weed. Control measures include stubbling, early autumn plowing, crop rotation with bare fallow, mowing on fallow grounds before flowering and use of herbicides if necessary.
Reference citations:Agaev M.G., ed. 1988. Main agricultural weeds in crops of the Leningrad region. Catalogue of VIR world collection. N 468. Leningrad: VIR. 112 p. (In Russian)
Anonymous. 1996. Weeds on sugar beet. Berlin: Hoehst Shering AgrEvo Gmbh. 479 p. (In Russian)
Keller B.A., Lyubimenko V.N., Maltsev A.I., Fedtshenko B.A., Shishkin B.K., Rodzevich R.Yu., Kamenskii K.V., eds. 1935. Weed plants of the USSR. V. 4. Moscow-Leningrad: AN USSR. 414 p. (In Russian)
Nikitin V.V. 1983. Weeds in the flora of the USSR. Leningrad: Nauka. 454 p. (In Russian)
Zakharenko V.A., Zakharenko A.V. 2004. Weed control. Zashchita i karantin rastenii 4: 62-142. (In Russian)