Ballota nigraL.

Black Horehoundblack horehound

WFO wfo-0000315321 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Ballota nigra, photographed by Nico
fig. a Nico, CC0 1.0 / 2022-06-12 / obs. 205509686

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 45 botanical countries

Regions where Ballota nigra is native: Algeria, Azores, Canary Is., Libya, Madeira, Morocco, Tunisia, Cyprus, East Aegean Is., Iran, Iraq, Lebanon-Syria, North Caucasus, Palestine, Transcaucasus, Türkiye, Albania, Baleares, Baltic States, Belarus, Belgium, Bulgaria, Central European Russia, Corse, Czechia-Slovakia, East European Russia, France, Germany, Greece, Hungary, Italy, Kriti, Krym, Northwest European Russia, NW. Balkan Pen., Poland, Portugal, Romania, Sardegna, Sicilia, South European Russia, Spain, Sweden, Türkiye-in-Europe, Ukraine AlgeriaLibyaMoroccoTunisiaCyprusEast Aegean Is.IranIraqLebanon-SyriaNorth CaucasusPalestineTranscaucasusTürkiyeAlbaniaBaltic StatesBelarusBelgiumBulgariaCentral European RussiaCorseCzechia-SlovakiaEast European RussiaFranceGermanyGreeceHungaryItalyKritiKrymNorthwest European RussiaNW. Balkan Pen.PolandPortugalRomaniaSiciliaSouth European RussiaSpainSwedenTürkiye-in-EuropeUkraine AzoresCanary Is.MadeiraBalearesSardegna
Native distribution of Ballota nigra, 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
Albania ALB EUROPE
Baleares BAL
Baltic States BLT
Belarus BLR
Belgium BGM
Bulgaria BUL
Central European Russia RUC
Corse COR
Czechia-Slovakia CZE
East European Russia RUE
France FRA
Germany GER
Greece GRC
Hungary HUN
Italy ITA
Kriti KRI
Krym KRY
Northwest European Russia RUW
NW. Balkan Pen. YUG
Poland POL
Portugal POR
Romania ROM
Sardegna SAR
Sicilia SIC
South European Russia RUS
Spain SPA
Sweden SWE
Türkiye-in-Europe TUE
Ukraine UKR
Cyprus CYP ASIA-TEMPERATE
East Aegean Is. EAI
Iran IRN
Iraq IRQ
Lebanon-Syria LBS
North Caucasus NCS
Palestine PAL
Transcaucasus TCS
Türkiye TUR
Algeria ALG AFRICA
Azores AZO
Canary Is. CNY
Libya LBY
Madeira MDR
Morocco MOR
Tunisia TUN

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 1,192 in flower of 1,461 examined

Proportion of examined Ballota nigra in flower, by month
Month In flower Examined Share 95% interval
Jan 3 9 33% 12% to 65%
Feb 0 12 0% 0% to 24%
Mar 1 28 4% 1% to 18%
Apr 2 102 2% 1% to 7%
May 40 102 39% 30% to 49%
Jun 256 281 91% 87% to 94%
Jul 316 322 98% 96% to 99%
Aug 221 230 96% 93% to 98%
Sep 170 173 98% 95% to 99%
Oct 121 127 95% 90% to 98%
Nov 55 62 89% 78% to 94%
Dec 7 13 54% 29% to 77%

Peak flowering in Sep. Each bar is the share of Ballota nigra 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. 1,192 of 1,461 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.

Where it actually grows measured, from 2,032 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -11.9 °C -3.7 °C 3.1 °C
Warmest month, mean daily high 19.9 °C 24.1 °C 28.1 °C
Annual rainfall 506 mm 627 mm 912 mm
Rainfall in the driest quarter 82 mm 114 mm 172 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 2,032 research-grade observations of Ballota nigra 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 43 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.

  • Ballota alba L.
  • Ballota alba var. borealis (Schweigg.) Nyman
  • Ballota ampliata Willd. ex Steud.
  • Ballota aristata Rchb.
  • Ballota borealis Schweigg.
  • Ballota bracteosa Ball
  • Ballota foetida Lam.
  • Ballota foetida var. glabrescens Boiss.
  • Ballota hirta Steud.
  • Ballota nigra f. borealis (Schweigg.) Bolzon
  • Ballota nigra f. uncinata Bég.
  • Ballota nigra subsp. meridionalis (Bég.) Bég.
  • Ballota nigra subsp. uncinata (Bég.) Patzak
  • Ballota nigra unranked variegata Abbey
  • Ballota nigra var. alba (L.) Tinant
  • Ballota nigra var. aurea Thys & Antoine
  • Ballota nigra var. foetida Vis.
  • Ballota nigra var. foetida Boiss.
  • Ballota nigra var. meridionalis Bég.
  • Ballota nigra var. mollissima Druce
  • Ballota nigra var. porrigens (Peterm.) Peterm.
  • Ballota nigra var. ruderalis (Sw.) Rchb.f.
  • Ballota nigra var. sericea Vandas
  • Ballota nigra var. submitis Borbás

and 19 more.

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.