Lobelia siphiliticaL.

great blue lobelia

WFO wfo-0000814885 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Lobelia siphilitica, photographed by vrschmalhofer
fig. a vrschmalhofer, CC BY 4.0 / 2021-09-26 / obs. 159915891
Lobelia siphilitica, photographed by Eric Knight
fig. b Eric Knight, CC BY 4.0 / obs. 160356232
Lobelia siphilitica, photographed by Yann Kemper
fig. c Yann Kemper, CC0 1.0 / obs. 162768226
Lobelia siphilitica, photographed by Brian Finzel
fig. d Brian Finzel, CC BY-SA 4.0 / obs. 174476323
Lobelia siphilitica, photographed by Brian Finzel
fig. e Brian Finzel, CC BY-SA 4.0 / obs. 174475041
Lobelia siphilitica, photographed by zancat
fig. f zancat, CC BY 4.0 / obs. 159948935
Lobelia siphilitica, photographed by Mark Richman
fig. g Mark Richman, CC BY 4.0 / obs. 159764713
Lobelia siphilitica, photographed by Patrick Hanly
fig. h Patrick Hanly, CC BY 4.0 / obs. 158817211

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.

Flowering n = 5,169 observations

Peak flowering in Sep, from 5,169 community-annotated observations worldwide. This is a global aggregate, not a forecast for your garden: the same species flowers on different dates in different hemispheres, and citizen-science records cluster near cities, at weekends, and in spring. Where a species has fewer than 30 annotated records we do not draw this chart at all.

Also published as 25 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.

  • Dortmanna siphilitica (L.) Kuntze
  • Lobelia antisyphilitica Hayne
  • Lobelia belgica De Jonghe
  • Lobelia bollii E.Wimm.
  • Lobelia coelestis Nutt. ex Loudon
  • Lobelia densiflora J.Rennie
  • Lobelia reflexa Stokes
  • Lobelia siphilitica f. alba (G.Don & W.H.Baxter) Voss
  • Lobelia siphilitica f. albiflora Britton
  • Lobelia siphilitica f. laevicalyx Fernald
  • Lobelia siphilitica f. ludoviciana (A.DC.) Voss
  • Lobelia siphilitica f. purpurea E.J.Palmer & Steyerm.
  • Lobelia siphilitica f. siphilitica
  • Lobelia siphilitica var. alba G.Don & W.H.Baxter
  • Lobelia siphilitica var. bollii (E.Wimm.) E.Wimm.
  • Lobelia siphilitica var. candida Alph.Wood
  • Lobelia siphilitica var. densiflora (J.Rennie) E.Wimm.
  • Lobelia siphilitica var. grandis E.Wimm.
  • Lobelia siphilitica var. ludoviciana A.DC.
  • Lobelia siphilitica var. maculata A.DC.
  • Lobelia siphilitica var. minor Hook.
  • Lobelia siphilitica var. rosea N.Coleman
  • Lobelia siphilitica var. siphilitica
  • Rapuntium siphiliticum (L.) Mill.

and 1 more.

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.

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