Alternate name: Common Wormwood
Family: Asteraceae, Aster view all from this family
Description Introduced perennial herb or subshrub; spreads by rhizome or self-seeds; may form large colonies.
Habit: weedy, invasive; upright branching stems, becoming woody and red to brown with age; faintly aromatic.
Height: 2-8 ft (60-180 cm) or more.
Leaf: alternate, deeply and irregularly lobed; dense silver down underneath; becoming narrower and less lobed above; 2-8 in (5-20 cm) long.
Flower: inconspicuous, to 1/8 in (3 mm) wide, pale green to yellow green to purple green; held in clusters along branches at top of plant, to 16 in (40 cm) long.
Fruit: tiny dry oblong seed, 1/32 in (1 mm) long, no hairs.
Habitat Sunny sites with sandy or loamy, high nitrogen soils: fields, roadsides, waste places, disturbed sites, forested areas, coastal strands.
Range Native to Eurasia; introduced as a medicinal plant and now naturalized across non-arctic Canada, and in the northwest, central, and eastern U.S.; California to Washington, east to Montana; and Maine to Florida, east to Minnesota, Kansas, and Louisiana; to 1650 ft (500 m).
Discussion Also known as: artemisia, chrysanthemum weed, common mugwort, common wormwood, felon-herb, green-ginger. Mugwort has been used medicinally since the Middle Ages and before. This plant is difficult to eradicate; it grows from stout, horizontal rhizomes that must be pulled or dug out if the plant is to be eliminated. It is considered an invasive plant pest in many areas, especially in the East.