common ragweed

Ragweed (Ambrosia artemisiifolia) Photo: Betty Marose

Updated: March 4, 2021

Life cycle: summer annual

Growth habit: grows 1 to 4 ft., erect, and branching; leaves pinnatifid, deeply dissected, fern-like; foliage similar to mugwort, but not chrysanthemum-scented and not from rhizomes; ragweed pollen is the primary cause of hay fever

Reproduction: by seed; green flowers inconspicuous, in terminal clusters

Conditions that favor growth: common in cultivated crops, orchards, roadsides, meadows, etc.; clay or sandy soil but prefers heavy, moist soils

Cultural control: does not tolerate frequent mowing

giant ragweed
Giant ragweed Photo:Ria Malloy