Asteraceae/Compositae (Aster/Composit Family) Synonym(s): Annual Ragweed, Short Ragweed Base Flower Color: Yellow, GreenReproductive Phenology: Jul, Aug, Sept, OctBloom Notes: This plant, not Goldenrod, is a cause of hay fever, recognized by all who suffer the discomfiting allergy. For more information about this plant, Click Here. Similar Species: Great Ragweed, Giant Ragweed (Ambrosia trifida L.)