Crocanthemum scoparium(Nutt.) Millsp.

Bisbee Peak rushrose

WFO wfo-0000626265 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Crocanthemum scoparium, photographed by Jeremiah Degenhardt
fig. a Jeremiah Degenhardt, CC BY 4.0 / 2022-05-21 / obs. 199705506

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.

The specimen a real sheet, in a real collection

Herbarium
The New York Botanical Garden
Accession
2544819
Filed as
Crocanthemum scoparium Millsp.
Det. by
J. Richard Abbott 2015-01-01
Collected
not recorded
Origin
not recorded
The sheet
View the digitised specimen (CC BY 4.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 2 botanical countries

Regions where Crocanthemum scoparium is native: California, Mexico Northwest CaliforniaMexico Northwest
Native distribution of Crocanthemum scoparium, 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.
RegionTDWG codeContinent
California CAL NORTHERN AMERICA
Mexico Northwest MXN

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 428 in flower of 442 examined

Proportion of examined Crocanthemum scoparium in flower, by month
Month In flower Examined Share 95% interval
Jan 18 21 86% 65% to 95%
Feb 25 25 100% 87% to 100%
Mar 49 50 98% 90% to 100%
Apr 85 88 97% 90% to 99%
May 117 118 99% 95% to 100%
Jun 47 48 98% 89% to 100%
Jul 18 19 95% 75% to 99%
Aug 19 19 100% 83% to 100%
Sep 9 10 90% 60% to 98%
Oct 21 23 91% 73% to 98%
Nov 10 10 100% 72% to 100%
Dec 10 11 91% 62% to 98%

Peak flowering in Feb. Each bar is the share of Crocanthemum scoparium 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. 428 of 442 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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.

When it blooms, where you are 1 state

StatePeaksObservations in flower
California Feb 419

Where it actually grows measured, from 1,974 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low 3.2 °C 6.9 °C 9.6 °C
Warmest month, mean daily high 18.3 °C 23.5 °C 31.2 °C
Annual rainfall 284 mm 515 mm 1,084 mm
Rainfall in the driest quarter 4 mm 6 mm 11 mm

It is found where winters are cool but frost is light or absent. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,974 research-grade observations of Crocanthemum scoparium 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. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 5 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.

  • Halimium aldersonii Standl.
  • Halimium scoparium (Nutt.) Grosser
  • Helianthemum scoparium Nutt.
  • Helianthemum scoparium var. vulgare Jeps.
  • Linum trisepalum Kellogg

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. USDA PLANTS Database. common name, checklist symbol HESC2. public domain. 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.