University of Maryland Extension



Ambrosia artemisiifolia


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

mature Ragweed
Ragweed (photo by Ria Malloy)

mature Giant ragweed
Giant ragweed Photo:Ria Malloy

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