Vascular Plants of North Carolina
Account for Giant Ragweed - Ambrosia trifida   L.
Members of Asteraceae:
Members of Ambrosia with account distribution info or public map:
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Section 6 » Order Asterales » Family Asteraceae
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DistributionMountains and Piedmont; absent from the Sandhills proper and almost all of the Coastal Plain.

N.S. to B.C., south to northern FL and CA.
AbundanceFrequent to common in the Mountains and Piedmont; very rare in the Coastal Plain. Much less numerous in these regions than is Common Ragweed (A. artemisiifolia).
HabitatAlluvial forests, especially where disturbed, farm yards, fallow fields, pastures. Favors moist or rich soils.
PhenologyFlowering and fruiting July-October.
IdentificationGiant Ragweed is unmistakable, with its deeply 3-lobed (sometimes 5-lobed) leaves and great height (3-12 feet). Inflorescences are much like Common Ragweed, but grow from leafy branches as well as terminally.
Taxonomic CommentsNone

Other Common Name(s)Great Ragweed
State RankS5
Global RankG5
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US Status
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B.A. Sorrieside of old road to boat ramp, above Carbonton MoorePhoto_natural
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