Ragweed

Asteraceae

LIFE FORM: Summer annual

NATIVITY: North America

VEGETATIVE CHARACTERISTICS:

Plant grows 1 to 3 feet tall; leaves are once or twice compound, mostly alternate.

FLOWERS:

Inconspicuous yellow-green flowers in dense, slender spikes making up the top 1/3 of the plant; they produce copious wind-dispersed pollen.

FRUIT:

Seeds spread readily and germinate in late spring on bare ground.

ECOLOGICAL PREFERENCE:

Minimally maintained public parks and open space; vacant lots and rubble dump sites; small-scale pavement openings (tree pits) and cracks; chain-link fence lines; rock outcrops and stone walls; unmowed highway banks and median strips with frequent salt applications; unmowed highway banks and median strips with frequent salt applications.

ENVIRONMENTAL FUNCTION:

Tolerant of road salt, making it common along roadways.

CULTURAL SIGNIFICANCE:

Its abundant pollen causes hay fever in late summer and early fall; used medicinally by native Americans.