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](/extension.umd.edu/sites/extension.umd.edu/files/styles/optimized/public/2021-03/hgic_weeds_giant_ragweed_600.jpg?itok=7daGFM4j)
![giant ragweed foliage](/extension.umd.edu/sites/extension.umd.edu/files/styles/optimized/public/2022-04/hgic_weeds_giant_ragweed_foliage_600.jpg?itok=w9INHhyW)
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