Great Ragweed

Ambrosia trifida

A most imposing weed, and like its cousin Common Ragweed (A. artimisiifolia), a source of hay fever for many. Distinguised from A. artimisiifolia not only by its greater size, but also by its leaves: this species has large, broad leaves that divide into three pointed lobes.  The flowering heads of this species are closer to 1/2 inch in diameter, and more prone to have numerous smaller sattelite heads growing out from the stem near the base of the main head.

5-15 feet, sun.

Late Summer (August-October).

Flowering heads with the three-pronged leaf clearly visible below.

11 August 2020.

Great Ragweed, 10 August 2020.