Hieracium scabrumMichx.

rough hawkweed

WFO wfo-0000037720 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Hieracium scabrum, photographed by Tom Field
fig. a Tom Field, CC BY 4.0 / 2021-09-21 / obs. 158833075

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
02456664
Filed as
Hieracium scabrum Michx.
Det. by
D. E. Atha 2015-01-01
Collected
D. E. Atha 2014-08-06
Origin
US
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 34 botanical countries

Regions where Hieracium scabrum is native: Arkansas, Connecticut, Delaware, District of Columbia, Georgia, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Brunswick, New Hampshire, New Jersey, New York, North Carolina, Nova Scotia, Ohio, Oklahoma, Ontario, Pennsylvania, Prince Edward I., Québec, Rhode I., South Carolina, Tennessee, Vermont, Virginia, West Virginia, Wisconsin ArkansasConnecticutGeorgiaIllinoisIndianaIowaKentuckyMaineMarylandMassachusettsMichiganMinnesotaMissouriNew BrunswickNew HampshireNew JerseyNew YorkNorth CarolinaNova ScotiaOhioOklahomaOntarioPennsylvaniaPrince Edward I.QuébecSouth CarolinaTennesseeVermontVirginiaWest VirginiaWisconsin DelawareDistrict of ColumbiaRhode I.
Native distribution of Hieracium scabrum, 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. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Arkansas ARK NORTHERN AMERICA
Connecticut CNT
Delaware DEL
District of Columbia WDC
Georgia GEO
Illinois ILL
Indiana INI
Iowa IOW
Kentucky KTY
Maine MAI
Maryland MRY
Massachusetts MAS
Michigan MIC
Minnesota MIN
Missouri MSO
New Brunswick NBR
New Hampshire NWH
New Jersey NWJ
New York NWY
North Carolina NCA
Nova Scotia NSC
Ohio OHI
Oklahoma OKL
Ontario ONT
Pennsylvania PEN
Prince Edward I. PEI
Québec QUE
Rhode I. RHO
South Carolina SCA
Tennessee TEN
Vermont VER
Virginia VRG
West Virginia WVA
Wisconsin WIS

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 331 in flower of 661 examined

Proportion of examined Hieracium scabrum in flower, by month
Month In flower Examined Share 95% interval
Jan 0 0 too few examined
Feb 0 0 too few examined
Mar 0 0 too few examined
Apr 0 0 too few examined
May 0 0 too few examined
Jun 0 2 too few examined
Jul 39 85 46% 36% to 56%
Aug 233 328 71% 66% to 76%
Sep 44 188 23% 18% to 30%
Oct 11 50 22% 13% to 35%
Nov 4 8 50% 22% to 78%
Dec 0 0 too few examined

Peak flowering in Aug. Each bar is the share of Hieracium scabrum 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. 331 of 661 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 7 months have fewer than 5 examined observations, so no proportion is drawn for them. 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.

Where it actually grows measured, from 966 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -15.8 °C -10.2 °C -2.9 °C
Warmest month, mean daily high 21.4 °C 25.6 °C 30.1 °C
Annual rainfall 840 mm 1,154 mm 1,456 mm
Rainfall in the driest quarter 98 mm 237 mm 320 mm

It is found where winters are severely cold. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 966 research-grade observations of Hieracium scabrum 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 2 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.

  • Hieracium marianum Willd.
  • Stenotheca mariana (Willd.) Monnier

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. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. 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.