Clethra alnifoliaL.

Sweet Pepperbush

WFO wfo-0000887989 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Clethra alnifolia, photographed by Lynn Harper
fig. a Lynn Harper, CC0 1.0 / 2022-02-19 / obs. 179961063
Clethra alnifolia, photographed by Lynn Harper
fig. b Lynn Harper, CC0 1.0 / obs. 192170890
Clethra alnifolia, photographed by Violet T.
fig. c Violet T., CC BY 4.0 / obs. 176531740
Clethra alnifolia, photographed by Zac Peterson
fig. d Zac Peterson, CC BY 4.0 / obs. 193411289
Clethra alnifolia, photographed by Tom Field
fig. e Tom Field, CC BY 4.0 / obs. 201548774
Clethra alnifolia, photographed by Lynn Harper
fig. f Lynn Harper, CC0 1.0 / obs. 200569905
Clethra alnifolia, photographed by Dan Bender
fig. g Dan Bender, CC BY 4.0 / obs. 200473173
Clethra alnifolia, photographed by Jim Arrigoni
fig. h Jim Arrigoni, CC BY 4.0 / obs. 178912704

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 = 1,656 observations

Peak flowering in Aug, from 1,656 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 16 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.

  • Clethra alnifolia f. alnifolia
  • Clethra alnifolia f. paniculata (Sol.) Schelle
  • Clethra alnifolia f. rosea Rehder
  • Clethra alnifolia var. alnifolia
  • Clethra alnifolia var. denudata Aiton
  • Clethra alnifolia var. glabella Michx.
  • Clethra alnifolia var. paniculata (Sol.) G.Nicholson
  • Clethra alnifolia var. paniculata Rehder
  • Clethra alnifolia var. rosea (Rehder) Rehder
  • Clethra angustifolia Raf.
  • Clethra bracteata Raf.
  • Clethra dentata Aiton
  • Clethra incana Pers.
  • Clethra paniculata Aiton
  • Clethra pubescens Willd.
  • Clethra pumila Raf.

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.