Alternate name: Annual Ragweed
Family: Asteraceae, Aster view all from this family
Description Native herbaceous annual.
Habit: many-branched, coarse, bushy; hairy stems, green to red; to 1-3 ft (.3-1 m) tall; breaks dormancy in late spring; taproot.
Leaf: deeply divided; opposite on lower stem, alternate on upper stem; to 6 in long x 4 in wide.
Flower: spike (raceme) of tiny yellow-green florets; 1-4 in long; held at tip of stem.
Fruit: tiny seeds enclosed in a hard bur.
Warning Plant parts can cause skin irritation if touched.
Flower July to October.
Habitat Disturbed sites, over-grazed pastureland, roadsides, prairies, meadows; sunny, average to dry sites.
Range Native or naturalized throughout non-arctic North America.
Discussion Considered weedy or invasive in some locations. Its pollen, dispersed by wind, is the primary cause of hay fever in late summer and fall. Despite its unpleasant effect on human beings, this plant is an important provider of food and cover to birds and insects. Also known as: annual ragweed, common ragweed, low ragweed, short ragweed, small ragweed, Roman wormwood.