Asclepias fascicularisDecne.

narrowleaf milkweed

WFO wfo-0000551316 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Asclepias fascicularis, photographed by Nicholas Wei
fig. a Nicholas Wei, CC BY-SA 4.0 / 2022-05-29 / obs. 202008994
Asclepias fascicularis, photographed by joergmlpts
fig. b joergmlpts, CC BY 4.0 / obs. 203963414
Asclepias fascicularis, photographed by Amthinkia
fig. c Amthinkia, CC0 1.0 / obs. 205034497
Asclepias fascicularis, photographed by Mary K. Hanson
fig. d Mary K. Hanson, CC BY 4.0 / obs. 171679859
Asclepias fascicularis, photographed by Millie Basden
fig. e Millie Basden, CC BY 4.0 / obs. 194326977
Asclepias fascicularis, photographed by Aaron Kreisberg
fig. f Aaron Kreisberg, CC BY 4.0 / obs. 200887503
Asclepias fascicularis, photographed by Henrik Kibak
fig. g Henrik Kibak, CC BY 4.0 / obs. 196546571
Asclepias fascicularis, photographed by Adam J. Searcy
fig. h Adam J. Searcy, CC BY 4.0 / obs. 200142851

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.

Confused withby our own model

These are not lookalikes we guessed at. Each one is a species our identification model genuinely mistook for this plant, and how many times. The error rate is published.

Flowering n = 3,147 observations

Peak flowering in Jul, from 3,147 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 3 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.

  • Asclepias fasciculata Hemsl.
  • Asclepias macrophylla Nutt.
  • Asclepias macrophylla var. comosa Durand & Hilg.

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.