Panicum capillareL.

Common Panic GrassOld-Witch Grasswitch grasswitchgrass

WFO wfo-0000883399 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Panicum capillare, photographed by Dylan Wishart
fig. a Dylan Wishart, CC BY 4.0 / 2021-12-17 / obs. 172639798

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 66 botanical countries

Regions where Panicum capillare is native: Alabama, Alberta, Arizona, Arkansas, British Columbia, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Manitoba, Maryland, Massachusetts, Mexico Northeast, Mexico Northwest, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Brunswick, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Nova Scotia, Ohio, Oklahoma, Ontario, Oregon, Pennsylvania, Prince Edward I., Québec, Rhode I., Saskatchewan, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming, Bermuda, Cuba, Jamaica, Leeward Is., Trinidad-Tobago, Windward Is. AlabamaAlbertaArizonaArkansasBritish ColumbiaCaliforniaColoradoConnecticutFloridaGeorgiaIdahoIllinoisIndianaIowaKansasKentuckyLouisianaMaineManitobaMarylandMassachusettsMexico NortheastMexico NorthwestMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew BrunswickNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaNova ScotiaOhioOklahomaOntarioOregonPennsylvaniaPrince Edward I.QuébecSaskatchewanSouth CarolinaSouth DakotaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyomingCubaJamaicaTrinidad-Tobago DelawareDistrict of ColumbiaRhode I.BermudaLeeward Is.Windward Is.
Native distribution of Panicum capillare, 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
Alabama ALA NORTHERN AMERICA
Alberta ABT
Arizona ARI
Arkansas ARK
British Columbia BRC
California CAL
Colorado COL
Connecticut CNT
Delaware DEL
District of Columbia WDC
Florida FLA
Georgia GEO
Idaho IDA
Illinois ILL
Indiana INI
Iowa IOW
Kansas KAN
Kentucky KTY
Louisiana LOU
Maine MAI
Manitoba MAN
Maryland MRY
Massachusetts MAS
Mexico Northeast MXE
Mexico Northwest MXN
Michigan MIC
Minnesota MIN
Mississippi MSI
Missouri MSO
Montana MNT
Nebraska NEB
Nevada NEV
New Brunswick NBR
New Hampshire NWH
New Jersey NWJ
New Mexico NWM
New York NWY
North Carolina NCA
North Dakota NDA
Nova Scotia NSC
Ohio OHI
Oklahoma OKL
Ontario ONT
Oregon ORE
Pennsylvania PEN
Prince Edward I. PEI
Québec QUE
Rhode I. RHO
Saskatchewan SAS
South Carolina SCA
South Dakota SDA
Tennessee TEN
Texas TEX
Utah UTA
Vermont VER
Virginia VRG
Washington WAS
West Virginia WVA
Wisconsin WIS
Wyoming WYO
Bermuda BER SOUTHERN AMERICA
Cuba CUB
Jamaica JAM
Leeward Is. LEE
Trinidad-Tobago TRT
Windward Is. WIN

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 35 in flower of 112 examined

Proportion of examined Panicum capillare in flower, by month
Month In flower Examined Share 95% interval
Jan 2 2 too few examined
Feb 1 1 too few examined
Mar 0 2 too few examined
Apr 0 1 too few examined
May 1 1 too few examined
Jun 1 1 too few examined
Jul 5 14 36% 16% to 61%
Aug 13 36 36% 22% to 52%
Sep 9 37 24% 13% to 40%
Oct 1 10 10% 2% to 40%
Nov 2 7 29% 8% to 64%
Dec 0 0 too few examined

Peak flowering in Aug. Each bar is the share of Panicum capillare 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. 35 of 112 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 2,019 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -14.6 °C -3.4 °C 5.6 °C
Warmest month, mean daily high 22.2 °C 27.9 °C 34.7 °C
Annual rainfall 435 mm 929 mm 1,349 mm
Rainfall in the driest quarter 37 mm 163 mm 259 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 2,019 research-grade observations of Panicum capillare 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 19 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.

  • Chasea capillaris (L.) Nieuwl.
  • Leptoloma barbipulvinata (Nash) Smyth
  • Leptoloma capillaris (L.) Smyth
  • Milium barbipulvinatum (Nash ex Rydb.) Lunell
  • Milium capillare (L.) Moench
  • Panicum acutifolium Willd. ex Spreng.
  • Panicum barbipulvinatum Nash ex Rydb.
  • Panicum barbipulvinatum var. hirsutipes Suksd.
  • Panicum bobartii Lam.
  • Panicum capillare subsp. barbipulvinatum (Nash ex Rydb.) Tzvelev
  • Panicum capillare subsp. capillare
  • Panicum capillare var. agreste Gatt.
  • Panicum capillare var. barbipulvinatum (Nash ex Rydb.) McGregor
  • Panicum capillare var. brevifolium Vasey
  • Panicum capillare var. capillare
  • Panicum capillare var. occidentale Rydb.
  • Panicum capillare var. vulgare Scribn.
  • Panicum elegantulum Suksd.
  • Panicum riparium H.Scholz

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.