Fraxinus anomala (single-leaf ash)

Plate 1 figs. a–h · 8 separate observations

Fraxinus anomala, photographed by Bobby McCabe — fig. a Bobby McCabe, CC BY 4.0 / 2021-10-15 / obs. 163606627

Fraxinus anomala, photographed by Cheryl McCleary-Catalano — fig. b Cheryl McCleary-Catalano, CC BY 4.0 / obs. 126150426

Fraxinus anomala, photographed by desertnaturalist — fig. c desertnaturalist, CC BY 4.0 / obs. 81863117

Fraxinus anomala, photographed by Matt Berger — fig. d Matt Berger, CC BY 4.0 / obs. 71884581

Fraxinus anomala, photographed by Erin Lalime — fig. e Erin Lalime, CC BY 4.0 / obs. 61954421

Fraxinus anomala, photographed by Parker Hopkins — fig. f Parker Hopkins, CC0 1.0 / obs. 61806994

Fraxinus anomala, photographed by runcator — fig. g runcator, CC BY 4.0 / obs. 43742682

Fraxinus anomala, photographed by Colin Croft — fig. h Colin Croft, CC BY 4.0 / obs. 45149355

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 7 botanical countries

Native distribution of Fraxinus anomala, 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.

Region	TDWG code	Continent
Arizona	ARI	NORTHERN AMERICA
California	CAL
Colorado	COL
Nevada	NEV
New Mexico	NWM
Utah	UTA
Wyoming	WYO

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.

Where it actually grows measured, from 1,555 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-9.3 °C	-5.9 °C	-0.9 °C
Warmest month, mean daily high	29.8 °C	33.0 °C	35.6 °C
Annual rainfall	185 mm	267 mm	402 mm
Rainfall in the driest quarter	27 mm	46 mm	61 mm

It is found where winters bring hard frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,555 research-grade observations of Fraxinus anomala that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one.

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.

Fraxinus anomala subsp. lowellii (Sarg. ex Rehder) A.E.Murray
Fraxinus anomala var. lowellii (Sarg. ex Rehder) Little
Fraxinus lowellii Sarg. ex Rehder

Sourcesevery claim on this page

World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
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.