Ageratina aromatica(L.) Spach

lesser snakeroot

WFO wfo-0000011501 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Ageratina aromatica, photographed by Lauren McLaurin
fig. a Lauren McLaurin, CC BY 4.0 / 2021-10-27 / obs. 166045164

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 21 botanical countries

Regions where Ageratina aromatica is native: Alabama, Connecticut, Delaware, District of Columbia, Florida, Georgia, Kentucky, Louisiana, Maryland, Massachusetts, Mississippi, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode I., South Carolina, Tennessee, Virginia, West Virginia AlabamaConnecticutFloridaGeorgiaKentuckyLouisianaMarylandMassachusettsMississippiNew JerseyNew YorkNorth CarolinaOhioPennsylvaniaSouth CarolinaTennesseeVirginiaWest Virginia DelawareDistrict of ColumbiaRhode I.
Native distribution of Ageratina aromatica, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Alabama ALA NORTHERN AMERICA
Connecticut CNT
Delaware DEL
District of Columbia WDC
Florida FLA
Georgia GEO
Kentucky KTY
Louisiana LOU
Maryland MRY
Massachusetts MAS
Mississippi MSI
New Jersey NWJ
New York NWY
North Carolina NCA
Ohio OHI
Pennsylvania PEN
Rhode I. RHO
South Carolina SCA
Tennessee TEN
Virginia VRG
West Virginia WVA

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 168 in flower of 190 examined

Proportion of examined Ageratina aromatica in flower, by month
Month In flower Examined Share 95% interval
Jan 0 0 too few examined
Feb 0 0 too few examined
Mar 0 0 too few examined
Apr 0 0 too few examined
May 0 0 too few examined
Jun 0 0 too few examined
Jul 3 6 50% 19% to 81%
Aug 12 16 75% 51% to 90%
Sep 71 79 90% 81% to 95%
Oct 72 76 95% 87% to 98%
Nov 9 12 75% 47% to 91%
Dec 1 1 too few examined

Peak flowering in Oct. Each bar is the share of Ageratina aromatica observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 168 of 190 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 7 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Also published as 20 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Ageratina aromatica var. aromatica
  • Ageratina cordata Spach
  • Eupatorium aromaticum L.
  • Eupatorium aromaticum var. melissoides (Willd.) A.Gray
  • Eupatorium ceanothifolium Muhl. ex Willd.
  • Eupatorium cordatum Walter
  • Eupatorium cordiforme Poiret
  • Eupatorium cordiforme Poir.
  • Eupatorium engelmannianum Link ex Torr. & A.Gray
  • Eupatorium latidens Small
  • Eupatorium melissoides Willd.
  • Eupatorium nemorale Greene
  • Eupatorium tracyi Greene
  • Eupatorium viburnifolium Greene
  • Kyrstenia aromatica (L.) Greene
  • Kyrstenia ceanothifolia Greene
  • Kyrstenia melissoides Greene
  • Kyrstenia nemoralis Greene
  • Kyrstenia tracyi Greene
  • Kyrstenia viburnifolia Greene

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.