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Rhododendron albrechtii; photograph Andreas Taeger, CC BY, iNaturalist via GBIF CC BYAndreas Taeger, CC BY, iNaturalist via GBIF

Rhododendron albrechtii Maxim.

Ericaceae · Japan · listed by its genus as a temperate garden plant

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Rhododendron albrechtii, photograph Andreas Taeger, CC BY, iNaturalist via GBIFRhododendron albrechtii, photograph Andreas Taeger, CC BY, iNaturalist via GBIFRhododendron albrechtii, photograph Andreas Taeger, CC BY, iNaturalist via GBIFRhododendron albrechtii, photograph Andreas Taeger, CC BY, iNaturalist via GBIFRhododendron albrechtii, photograph Andreas Taeger, CC BY, iNaturalist via GBIFRhododendron albrechtii, photograph Andreas Taeger, CC BY, iNaturalist via GBIF 23 photographs ›
Habitat figures
Cold floor (1 night in 100)
-14.9°C
Record low -21.9 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
24°C
Aug at the habitat CHELSA
Rain a year (median across the range)
2,483mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
13–34DLI
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
Rain spread: 70% of the median year's rain takes 8 months, so no short rainy season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Rhododendron albrechtii is a species of flowering plant in the family Ericaceae. It is endemic to Japanese temperate rainforests. Native of central and northern Japan; described from specimens collected in the 1860s by Michael Albrecht of the Russian Consulate at Hakodate, for whom the species is named.

Quoted from Wikipedia, "Rhododendron albrechtii", 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

Grouped as a temperate garden plant, listed under the genus Rhododendron in the archetype table, and Kew describes it as “shrub”, “temperate”.

Seasons

The rain rule reads no short rainy season: 70% of the median year's rain (1,846 mm of 2,459 mm) takes 8 months, May to December. Mean temperature moves 25.8 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to June.

Rain

2,459 mm in the median year at the habitat, 1,846 mm of it May to December. Wettest month July at 306 mm, driest month February at 135 mm. Across the grid cells of the range the year's total runs 1,691 mm to 3,477 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 2,483 mm, is the year's rain at the top of the page; the 2,459 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: 13 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 10, the highest 90th-percentile month 37).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -14.9 °C, the absolute minimum -21.9 °C, 7,072 frost nights in 44 years, 160.7 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 28.8 °C. Monthly means: the coldest month's mean nightly low -10.3 °C in January (across the grid cells of the range -13.7 °C to -6.7 °C), the warmest month's mean daily high 24.3 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: -14.9 °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: 60 to 68% 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 +324 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.

Group. Listed under the genus Rhododendron in the archetype table, and Kew describes it as “shrub”, “temperate”. A group is taken only where Kew's description of the species agrees with the table's listing. The table gives no figure and no prose; the cold floor is the habitat's alone.

Climate across the habitat

Habitat months, northern hemisphere

Habitat climate of Rhododendron albrechtii through the yearWarmest month August, mean daily high 24 °C; coldest month January, mean nightly low -10.3 °C; 2,459 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.-30°-20°-10°0°10°20°30°frost28.8° 99th-percentile day, NASA POWER-21.9° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0100200300400500mm rainDLI 13–34RH 60–68%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 160 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 °C-2 / -6–1-2 / -5–23 / -1–510 / 6–1216 / 13–1820 / 17–2223 / 20–2524 / 21–2720 / 17–2214 / 11–167 / 4–101 / -3–4
Night °C-10 / -14–-7-9 / -13–-6-5 / -9–-31 / -3–37 / 3–912 / 8–1416 / 13–1817 / 14–1913 / 10–156 / 3–9-1 / -4–2-7 / -11–-4
Rain mm162 / 71–338135 / 74–229161 / 106–231155 / 105–219184 / 130–249219 / 161–289306 / 218–427267 / 171–388290 / 226–351208 / 147–282193 / 95–322179 / 68–341
DLI15 / 13–1821 / 18–2427 / 26–3033 / 31–3634 / 32–3732 / 30–3529 / 27–3330 / 27–3323 / 21–2620 / 18–2215 / 13–1813 / 10–16
RH %66 / 61–7065 / 60–6862 / 59–6460 / 57–6261 / 59–6365 / 62–6768 / 65–7167 / 64–7067 / 64–6964 / 61–6664 / 60–6665 / 60–69
How this section is made
Each figure is the median across the 160 grid cells holding the 172 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 1063:6372 (36.825, 138.625). Over 44 years there: absolute minimum -21.9 °C, 1st-percentile night -14.9 °C, 99th-percentile day 28.8 °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 160 distinct grid cells holding 172 of the 172 in-range records; extremes and elevation at the typical cell 1063:6372 (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 37.00_138.750, lapse-corrected +324 m at 6.5 °C/km. Elevation: ETOPO 2022, 1108 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 · 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 marker36.81, 138.438 · in the densest population, 569 records (88% of those in range)
Kew's description“shrub” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 647 georeferenced records inside the native range; the climate across the range on the 172 of them placed to within 10 km; the map shows only the 624 openly licensed ones, which alone would put the marker 2 km away. 4 records outside the WCVP native range not used. 475 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 647 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 albrechtii, photograph 1did not loadRhododendron albrechtii, photograph 2did not loadRhododendron albrechtii, photograph 3did not loadRhododendron albrechtii, photograph 4did not loadRhododendron albrechtii, photograph 5did not loadRhododendron albrechtii, photograph 6did not load

Photographs: Andreas Taeger, CC BY, iNaturalist via GBIF (6).

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

Viola brevistipulata Viola brevistipulata Short Stipule Violet Photo: CC BY, Yoshihiro TokueAcer nipponicum Acer nipponicum Nippon maple Photo: CC BY, りなべるRhododendron nipponicum Rhododendron nipponicum Ericaceae Photo: CC BY-SA, Qwert1234Eubotryoides grayana Eubotryoides grayana Ericaceae Photo: CC BY-SA, Qwert1234Ilex sugerokii Ilex sugerokii Aquifoliaceae Photo: CC BY, Jacy ChenPatrinia gibbosa Patrinia gibbosa Caprifoliaceae Photo: CC BY, Илья Руденко

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 albrechtii; Rhododendron albrechtii f. albiflorum; Rhododendron albrechtii f. canescens; Rhododendron albrechtii f. hypoleucum. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipedia

The record

Family
Ericaceae
Described by
Maxim.
Native to
Japan
Wild records
647 in range · 624 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; 15 records within 1 km of a botanic garden, herbarium or zoo left out (15 at a botanic garden or arboretum; 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 37.00_138.750, lapse-corrected +324 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-22
Wikipedia wikipedia answeredasked 2026-10-22
iNaturalist taxon inat.taxon not asked
iNaturalist photographs, wild inat.photos.wild not asked
iNaturalist photographs, cultivated inat.photos.cultivated not asked
GBIF media gbif.media answeredasked 2026-10-22
Wikimedia Commons commons 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 45 datasets via GBIF.org; each carries its own licence.

Cultifolio

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