Rhododendron hirsutum (Hairy Alpenrose)

Plate 1 figs. a–h · 8 separate observations

Rhododendron hirsutum, photographed by Jason Grant — fig. a Jason Grant, CC BY 4.0 / 2022-05-12 / obs. 197079071

Rhododendron hirsutum, photographed by Philipp Pavelka — fig. b Philipp Pavelka, CC BY 4.0 / obs. 193699073

Rhododendron hirsutum, photographed by Marco Mussita — fig. c Marco Mussita, CC BY 4.0 / obs. 163074469

Rhododendron hirsutum, photographed by Caleb Catto — fig. d Caleb Catto, CC BY 4.0 / obs. 162105600

Rhododendron hirsutum, photographed by kfa — fig. f kfa, CC0 1.0 / obs. 154158353

Rhododendron hirsutum, photographed by Philipp — fig. g Philipp, CC BY 4.0 / obs. 152236867

Rhododendron hirsutum, photographed by Yves Bas — fig. h Yves Bas, CC BY 4.0 / obs. 161213210

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 Rhododendron hirsutum, 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.

Region	TDWG code	Continent
Austria	AUT	EUROPE
France	FRA
Germany	GER
Italy	ITA
NW. Balkan Pen.	YUG
Switzerland	SWI

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 429 in flower of 511 examined

83%

96%

81%

32%

14%

Proportion of examined Rhododendron hirsutum in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	1	too few examined
Feb	0	0	too few examined
Mar	0	2	too few examined
Apr	0	3	too few examined
May	0	8	0%	0% to 32%
Jun	91	110	83%	75% to 89%
Jul	257	267	96%	93% to 98%
Aug	74	91	81%	72% to 88%
Sep	6	19	32%	15% to 54%
Oct	1	7	14%	3% to 51%
Nov	0	1	too few examined
Dec	0	2	too few examined

Peak flowering in Jul. Each bar is the share of Rhododendron hirsutum 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. 429 of 511 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 6 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 2,006 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-16.3 °C	-11.6 °C	-6.6 °C
Warmest month, mean daily high	13.5 °C	16.4 °C	21.7 °C
Annual rainfall	1,111 mm	1,741 mm	2,637 mm
Rainfall in the driest quarter	148 mm	278 mm	493 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 2,006 research-grade observations of Rhododendron hirsutum 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 8 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.

Azalea hirsuta (L.) Kuntze
Chamaerhododendron hirsutum (L.) Bubani
Rhododendron angustifolium Hoppe
Rhododendron germanicum Hoppe
Rhododendron glabratum Hoppe
Rhododendron hirsutum var. variegatum G.Don
Rhododendron intermedium Schur
Rhododendron latifolium Hoppe

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.