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Rhododendron × pulchrum; photograph (c) Doreen, some rights reserved (CC BY) CC BY(c) Doreen, some rights reserved (CC BY) · observed growing wild · 2026-05-16

Rhododendron × pulchrum Sweet

Ericaceae · Japan

A hybrid: R. mucronatum × R. scabrum, the parents Kew's World Checklist states for it (WCVP, RBG Kew).

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Rhododendron × pulchrum, photograph (c) Gabriel, some rights reserved (CC BY)Rhododendron × pulchrum, photograph (c) Liem Malarney, some rights reserved (CC BY)Rhododendron × pulchrum, photograph (c) Carlos Alexandre Mattos Raposo, some rights reserved (CC BY)Rhododendron × pulchrum, photograph (c) Carlos Alexandre Mattos Raposo, some rights reserved (CC BY)Rhododendron × pulchrum, photograph (c) 卢江离, some rights reserved (CC BY)Rhododendron × pulchrum, photograph (c) Shaun Swanepoel, some rights reserved (CC BY) 20 photographs ›
Habitat figures
Cold floor (1 night in 100)
-3.5°C
Record low -8.7 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
30°C
Aug at the habitat CHELSA
Rain a year (median across the range)
1,615mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
15–34DLI
Lowest to highest month (DLI) CHELSA
The year in your months, northern hemisphere
  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec
Wet summers: the rain comes April to October, read as a summer growing season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Rhododendron pulchrum (锦绣杜鹃), also identified as Rhododendron × pulchrum, is a rhododendron endemic to China. It grows as a semi-evergreen shrub, 1.5–2.5 m (4.9–8.2 ft) in height, with leathery leaf blades, elliptic-oblong to elliptic-lanceolate or oblong-oblanceolate, 2–5(–7) × 1–2.5 cm in size. The flowers are rose-purple with dark red flecks. Hirsutum describes it as "a natural hybrid; seed × pollen= R. mucronatum var mucronatum × R. indicum var formosanum".

Quoted from Wikipedia, "Rhododendron pulchrum", CC BY-SA 4.0.

About the genus · Rhododendron

Rhododendron, from Ancient Greek ῥόδον (rhódon), meaning "rose", and δένδρον (déndron), meaning "tree", is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are native to eastern Asia and the Himalayan region, but smaller numbers occur elsewhere in Asia, and in North America, Europe and Australia.

Quoted from Wikipedia, "Rhododendron", CC BY-SA 4.0.

Cultivation

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (1,245 mm of 1,643 mm) falls in April to October, warmer than the year (wet-season mean 21.0 °C against a yearly mean of 15.5 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: October to April.

Rain

1,643 mm in the median year at the habitat, 1,245 mm of it April to October. Wettest month September at 215 mm, driest month December at 54 mm. Across the grid cells of the range the year's total runs 1,450 mm to 2,526 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,615 mm, is the year's rain at the top of the page; the 1,643 mm here is the median year's, the twelve monthly medians added, which the rain rule reads. Habitat calendar, northern hemisphere; median year across the grid cells of the range, CHELSA.

Light

Open sky over the habitat: 15 to 34 mol/m²/day across the year (daily light integral, median year across the grid cells of the range, CHELSA; the lowest 10th-percentile month across the cells is 14, the highest 90th-percentile month 35).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -3.5 °C, the absolute minimum -8.7 °C, 2,328 frost nights in 44 years, 52.9 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 35.2 °C. Monthly means: the coldest month's mean nightly low 0.4 °C in January (across the grid cells of the range -1.2 °C to 3.3 °C), the warmest month's mean daily high 29.6 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: -3.5 °C, which is the 1st-percentile night over 44 years at a typical spot in the range (NASA POWER).

Humidity

Relative humidity at the habitat: 56 to 66% across the year (monthly means, median year across the grid cells of the range, CHELSA). A figure about the air, saying nothing about how the plant takes water.

How this section is made

Each card states this species' habitat figures with their sources, and what two fixed rules read from them; nothing here says what the plant does, wants or tolerates. The rules · the terms.

Seasons. Read from the median year of CHELSA monthly rainfall and mean temperature across the grid cells of the range: the rain rule takes the smallest set of months carrying 70% of the rain and calls it winter when its mean is more than half a degree below the year's, summer when more than that above, and neither in between; the temperature rule, used only under 120 mm, names the cooler six months when they are at least a degree cooler than the other six. Months are shifted for the other hemisphere only where the temperature curve moves 4 °C or more and the habitat lies 10° or more from the equator. A reading of the curves, not an observation of the plant.

Rain. CHELSA monthly precipitation, median year across the grid cells of the range. The rain that falls where the species is recorded; nothing about how the plant takes water.

Light. CHELSA shortwave radiation at each envelope cell, a daily-mean flux taken to a daily total and converted at 2.07 mol of PAR per MJ. The sky over the habitat, measured; what reaches a plant under a rock, a shrub or a shade cloth is not.

Temperature. NASA POWER daily minima and maxima over 44 years at a typical spot in the range, lapse-corrected -196 m to its elevation; CHELSA monthly means, median year across the grid cells of the range. The cold floor is the 1st-percentile night named in its sentence. Not a measured survival limit for any plant in a pot.

Humidity. CHELSA relative humidity, median year across the grid cells of the range.

Climate across the habitat

Habitat months, northern hemisphere

Habitat climate of Rhododendron × pulchrum through the yearWarmest month August, mean daily high 30 °C; coldest month January, mean nightly low 0.4 °C; 1,643 mm of rain in the median year (the twelve monthly medians added). Medians across the range, from CHELSA; the extremes at the edge from NASA POWER. Habitat months, northern hemisphere.-10°0°10°20°30°40°frost35.2° 99th-percentile day, NASA POWER-8.7° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0100200300400mm rainDLI 15–34RH 56–66%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 20 habitat cells, CHELSA cold quarter: the three months around the coldest month's mean nightly low extremes over 44 years at a typical spot in the range, from NASA POWER, marked at the edge, in no month DLI, mol/m²/dayRH %each on its own scale
Figures by month
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C8 / 7–99 / 7–1012 / 11–1317 / 16–1821 / 20–2224 / 23–2628 / 27–2930 / 28–3126 / 25–2720 / 20–2215 / 14–1711 / 9–12
Night °C0 / -1–31 / -1–44 / 2–69 / 8–1114 / 12–1518 / 17–1922 / 21–2323 / 23–2420 / 19–2114 / 13–168 / 7–113 / 2–6
Rain mm59 / 47–12572 / 51–146120 / 103–180130 / 114–174157 / 129–217203 / 162–316198 / 157–303172 / 122–224215 / 176–270170 / 116–19493 / 79–15154 / 46–121
DLI17 / 15–1822 / 21–2326 / 25–2832 / 30–3334 / 32–3531 / 28–3332 / 29–3333 / 30–3426 / 23–2722 / 19–2417 / 16–1815 / 14–17
RH %56 / 53–5956 / 54–5958 / 56–5959 / 57–6162 / 60–6365 / 63–6866 / 64–6965 / 62–6864 / 62–6561 / 60–6259 / 58–6057 / 55–60
How this section is made
Each figure is the median across the 20 grid cells holding the 20 in-range records, with the 10th–90th percentile span across those cells after the slash where it differs. A dash is a month one or more of those cells has no figure for in the grid (a variable CHELSA does not carry there), so no median is taken rather than one over fewer cells. Extremes and elevation were read at a typical spot in the range, cell 1086:6393 (35.675, 139.675). Over 44 years there: absolute minimum -8.7 °C, 1st-percentile night -3.5 °C, 99th-percentile day 35.2 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Across the range: median and 10th–90th percentile of each month across the 20 distinct grid cells holding 20 of the 20 in-range records; extremes and elevation at the typical cell 1086:6393 (its coldest month's mean nightly low nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell 35.50_139.375, lapse-corrected -196 m at 6.5 °C/km. Elevation: ETOPO 2022, 37 m (cell mean).

Natural habitat

Native range as published by WCVP; the marker is where the records are densest and decides nothing: the climate was read across the cells of the in-range records placed well enough to read one, not at the marker.
Openly licensed records inside the range, framed on where they fall.
NativeJapan · introduced: China Southeast · regions are the level-3 units of the World Geographical Scheme for Recording Plant Distributions, as Kew's World Checklist records ranges, some under historical names such as Yugoslavia or Czechoslovakia (how).
Map marker35.582, 139.406 · in the densest population, 35 records (67% of those in range)
Kew's description“shrub” · “subtropical” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 52 georeferenced records inside the native range; the climate across the range on the 20 of them placed to within 10 km; the map shows only the 37 openly licensed ones, which alone would put the marker 59 km away. 100 records outside the WCVP native range not used. 32 in-range records are placed to worse than 10 km, or with no stated accuracy (admitted only as a person's observation to three decimals), and stay on the map but off the climate.
How this section is made
The map marker: the openly licensed record nearest the middle of the densest 1° population inside the densest 2° block of the 52 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Rhododendron × pulchrum, photograph 1did not loadRhododendron × pulchrum, photograph 2did not loadRhododendron × pulchrum, photograph 3did not loadRhododendron × pulchrum, photograph 4did not loadRhododendron × pulchrum, photograph 5did not loadRhododendron × pulchrum, photograph 6did not load

Photographs: (c) Gabriel, some rights reserved (CC BY); (c) Liem Malarney, some rights reserved (CC BY); (c) Carlos Alexandre Mattos Raposo, some rights reserved (CC BY) (2); (c) 卢江离, some rights reserved (CC BY); (c) Shaun Swanepoel, some rights reserved (CC BY).

Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.

Lycoris × albiflora Lycoris × albiflora White-flower surprise lily Photo: CC BY, Jhonatan MatheusTaraxacum albidum Taraxacum albidum Asteraceae Photo: CC BY, 大澤風季 ohsawa_FukiBletilla striata Bletilla striata Hyacinth orchid Photo: CC BY, W RaoHydrangea macrophylla Hydrangea macrophylla French hydrangea Photo: CC BY, Claude KolwelterReineckea carnea Reineckea carnea Kichijo-so Photo: CC BY, Saryu Mae 前 朝琉Lycoris radiata Lycoris radiata Red spider lily Photo: CC BY, Kevin Jones

Other Rhododendron 574 in the reference

Rhododendron aberconwayi Rhododendron aberconwayi Ericaceae Photo: Public domain, Daderot Rhododendron abietifolium Ericaceae Rhododendron acrophilum Ericaceae Rhododendron adamsii Rhododendron adamsii Sagan Dalya Photo: CC BY, Valentin KosterinRhododendron adenogynum Rhododendron adenogynum Ericaceae Photo: CC BY-SA, Kurt StüberRhododendron adenopodum Rhododendron adenopodum Ericaceae Photo: CC BY-SA, Ulf EliassonRhododendron adenosum Rhododendron adenosum Ericaceae Photo: CC0, DaderotRhododendron aeruginosum Rhododendron aeruginosum Ericaceae Photo: CC BY, Siddarth MachadoRhododendron aganniphum Rhododendron aganniphum Ericaceae Photo: CC0, Daderot Rhododendron agathodaemonis Ericaceae Rhododendron alabamense Rhododendron alabamense Alabama azalea Photo: CC BY, Rob JohnRhododendron albiflorum Rhododendron albiflorum White rhododendron Photo: CC0, author not stated all 575 ›

Names & registers

Also known as Azalea indica subsp. hybrida; Azalea indica var. calycina; Azalea indica var. phoenicea; Azalea indica var. rawsonii; Azalea rosmarinifolia var. purpurea and 11 more. (GBIF Backbone)

Under another author Rhododendron maxwellii Millais is an older name of this species, not Rhododendron maxwellii, a species of the reference. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Ericaceae
Described by
Sweet
Native to
Japan
Wild records
52 in range · 37 open

Every figure here is derived from public data by a stated rule and names its source; nothing about this species is written for its page by a person or by AI, apart from the marked, credited quotations. How →

Where this page came from built 2026-10-22
GBIF species record gbif.species answeredasked 2026-10-22
GBIF synonyms gbif.synonyms answeredasked 2026-10-22
GBIF common names gbif.vernacular answeredasked 2026-10-22names fetched 2026-10-22
WCVP native range wcvp.distribution answeredas of 2026-06-04
GBIF occurrence records gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 32 records within 1 km of a botanic garden, herbarium or zoo left out (20 at a botanic garden or arboretum, 7 at a herbarium, 5 at a zoo; Wikidata's list)
Habitat climate climate answeredasked 2026-10-22
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 35.50_139.375, lapse-corrected -196 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-22
Wikipedia wikipedia answeredasked 2026-10-22
iNaturalist photographs, wild inat.photos.wild answeredasked 2026-10-22from iNaturalist's open data of 2026-09-27: research-grade observations with an open-licence photograph, the 24 whose photographs iNaturalist received last (the open data holds no votes); filled 2026-10-22
iNaturalist photographs, cultivated inat.photos.cultivated not asked
GBIF media gbif.media answeredasked 2026-10-22
OpenAlex papers openalex not askednot yet asked for this reference; a later fill takes the papers from OpenAlex's snapshot

Every source is recorded as having answered, reported nothing, refused, failed, not been asked, or answered twice where one answer is taken (“not taken: two items answered”), and, for a source asked when this page was built, when: the figures are as the source held them that day; a source read from a file (Kew's World Checklist, a GBIF download) says "as of" the file's day instead; a row carried from an earlier build of the page names that build instead. Only “nothing to report” is ever shown as an absence. Records came from 24 datasets via GBIF.org; each carries its own licence.

Cultifolio

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