Giant ragweed
Ambrosia trifida L.
- light
- —
- water
- —
- tall
- 2.0 m
- wide
- —
Asteraceae
Also called Annual ragweed, Great ragweed, Horse-cane, Great Ragweed
Formerly Ambrosia aptera, Ambrosia integrifolia
When it flowers
Not known yet in the tropics: too few flowering observations to read a season from.
Read from iNaturalist photographs of it in flower. A month counts at 50% of the best month's flowering share (smoothed over three months) and 10% of its flowering count, from at least 100 flowering observations in the band.
If a child, a pet or anyone may have eaten a plant, contact a doctor or vet straight away, or call the National Poisons Information Centre (AIIMS, New Delhi) on 1800 116 117, free and open 24 hours.
Something wrong with it?About it
- Grows as
- AnnualKew's checklist, not yet checked
- Climate
- TemperateKew's checklist, not yet checked
- Wild in
- N. AmericaKew's checklist, not yet checked
- Height
- 2.0 mRead from Wikipedia and Plants for a Future, checked by a majority of its sourcesBacked by both sources
Not known yet: light, spread, water, flowers, coldest it survives, heat, hottest it survives.
In other languages (12)
- root
- AMBTRI, ᎤᏆᏍᏓᎷᏱᏓ, vtakrv-homv-rakko
- Japanese
- オオブタクサ
- French
- ambroisie trifide, Grande herbe à poux
- Czech
- ambrozie trojklaná
- Dutch
- Driedelige ambrosia, Drielobbige ambrosia
- Finnish
- sormituoksukki
- Russian
- Амброзия трёхраздельная
- German
- Dreilappiges Traubenkraut, Dreispaltige Ambrosie
- Lithuanian
- Triskiautė ambrozija
- Estonian
- kolmehõlmane ambroosia
- Korean
- 단풍잎돼지풀
- Chinese (China)
- 三裂叶豚草, 大豚草
Where this comes from
- iNaturalist, read 2026-10-26, CC0-1.0 (observation counts)
- Wikidata, read 2026-10-25, CC0-1.0
- Kew's checklist, read 2026-10-24, CC-BY-4.0
- Wikipedia, read 2026-10-26, fact, cited
- Plants for a Future, read 2026-10-26, fact, cited
- Wikimedia Commons, read 2026-10-25, CC BY-SA 3.0
- iNaturalist, read 2026-10-26, CC BY-SA
- iNaturalist, read 2026-10-26, CC0
- iNaturalist, read 2026-10-26, CC BY
- 3D model: Ambrosia trifida (built for Vanagrha) by Vanagrha, own
A fact “checked by a majority of its sources” was settled by a vote of the pages it was read from, not by a person reading it; one marked “one source” rests on that page alone. Anything else not marked checked has not been checked yet. Where nothing is known, the page says so rather than guess.