Marrubium incanum (Silver Horehound)

Plate 1 figs. a–h · 6 observations

This species has been photographed under an open licence only 6 times, so some figures below are different views of the same plant, taken on the same day, rather than different individuals. They are usually different parts of it: the leaf, the flower, the bark.

Marrubium incanum, photographed by Pavel Kacl — fig. a Pavel Kacl, CC BY 4.0 / 2021-09-29 / obs. 160513423

Marrubium incanum, photographed by Yves Bas — fig. b Yves Bas, CC BY 4.0 / obs. 154303834

Marrubium incanum, photographed by Christian Berg — fig. c Christian Berg, CC BY 4.0 / obs. 135529559

Marrubium incanum, photographed by Emanuele Santarelli — fig. d Emanuele Santarelli, CC BY-SA 4.0 / obs. 77488758

Marrubium incanum, photographed by viridian — fig. g viridian, CC0 1.0 / obs. 77305346

Marrubium incanum, photographed by Thor-Rune Hansen — fig. h Thor-Rune Hansen, CC BY-SA 4.0 / obs. 162860801

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 6 botanical countries

Native distribution of Marrubium incanum, 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.

Region	TDWG code	Continent
Albania	ALB	EUROPE
Bulgaria	BUL
Italy	ITA
NW. Balkan Pen.	YUG
Sardegna	SAR
Sicilia	SIC

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 294 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-4.8 °C	-0.8 °C	6.1 °C
Warmest month, mean daily high	21.5 °C	25.2 °C	28.9 °C
Annual rainfall	835 mm	1,174 mm	2,100 mm
Rainfall in the driest quarter	126 mm	195 mm	337 mm

It is found where winters bring light 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 294 research-grade observations of Marrubium incanum 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.

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.