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Hemerocallis yezoensis; photograph (c) Francisca Wu, some rights reserved (CC BY) CC BY(c) Francisca Wu, some rights reserved (CC BY) · observed growing wild · 2025-07-03

Hemerocallis yezoensis H.Hara

Asphodelaceae · Kuril Is., Japan · listed by its genus as a temperate garden plant

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Hemerocallis yezoensis, photograph (c) Rajan Rao, some rights reserved (CC BY)Hemerocallis yezoensis, photograph Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia CommonsHemerocallis yezoensis, photograph Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia CommonsHemerocallis yezoensis, photograph Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia CommonsHemerocallis yezoensis, photograph Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia CommonsHemerocallis yezoensis, photograph Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons 7 photographs ›
Habitat figures
Cold floor (1 night in 100)
-14.6°C
Record low -20.3 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
19°C
Aug at the habitat CHELSA
Rain a year (median across the range)
1,310mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
10–34DLI
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 May to November, 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

Hemerocallis yezoensis (Japanese: エゾキスゲ, romanized: ezokisuge, Russian: Красоднев иезский, romanized: Krasodnev iyezskiy) is a species of plant in the genus Hemerocallis, native to eastern Hokkaido and the southernmost extremities of the Kuril Islands.

Quoted from Wikipedia, "Hemerocallis yezoensis", CC BY-SA 4.0.

About the genus · Hemerocallis

A daylily, day lily or ditch-lily is a flowering plant in the genus Hemerocallis, a member of the family Asphodelaceae, subfamily Hemerocallidoideae, native to Asia. Despite the common name, it is not taxonomically classified in the lily genus. Gardening enthusiasts and horticulturists have long bred Hemerocallis species for their attractive flowers; a select few species of the genus have edible petals, while some are extremely toxic. More on Wikipedia ›

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

Cultivation

Grouped as a temperate garden plant, listed under the genus Hemerocallis in the archetype table, and Kew describes it as “perennial or tuberous geophyte”, “temperate”.

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (980 mm of 1,323 mm) falls in May to November, warmer than the year (wet-season mean 11.4 °C against a yearly mean of 5.7 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to May.

Rain

1,323 mm in the median year at the habitat, 980 mm of it May to November. Wettest month September at 191 mm, driest month February at 43 mm. Across the grid cells of the range the year's total runs 984 mm to 1,753 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,310 mm, is the year's rain at the top of the page; the 1,323 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: 10 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 9, 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 -14.6 °C, the absolute minimum -20.3 °C, 6,170 frost nights in 44 years, 140.2 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 28.8 °C. Monthly means: the coldest month's mean nightly low -8.8 °C in February (across the grid cells of the range -9.4 °C to -7.7 °C), the warmest month's mean daily high 19.1 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: -14.6 °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: 57 to 73% 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 -84 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 Hemerocallis in the archetype table, and Kew describes it as “perennial or tuberous geophyte”, “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 Hemerocallis yezoensis through the yearWarmest month August, mean daily high 19 °C; coldest month February, mean nightly low -8.8 °C; 1,323 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-20.3° lowest night in 44 years, NASA POWER°C · day and nightcold quarter050100150200250mm rainDLI 10–34RH 57–73%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 12 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-3 / -3–-2-4 / -5–-2-1 / -2–24 / 3–79 / 6–1212 / 9–1616 / 13–2019 / 17–2217 / 16–1813 / 12–147 / 6–81 / 0–2
Night °C-7 / -9–-5-9 / -9–-8-5 / -6–-40 / -1–15 / 4–59 / 8–1013 / 12–1416 / 15–1714 / 14–149 / 8–103 / 2–4-3 / -5–-1
Rain mm64 / 49–7343 / 32–4876 / 58–9791 / 67–108138 / 83–166112 / 72–134151 / 110–178158 / 125–219191 / 137–240129 / 88–171101 / 69–12869 / 59–85
DLI12 / 11–1419 / 18–2028 / 27–2833 / 32–3334 / 33–3534 / 32–3531 / 29–3228 / 26–2923 / 23–2419 / 18–1912 / 12–1410 / 9–12
RH %59 / 57–6262 / 58–6462 / 58–6463 / 60–6565 / 62–6870 / 65–7373 / 67–7671 / 66–7466 / 62–6660 / 59–6258 / 57–6057 / 56–60
How this section is made
Each figure is the median across the 12 grid cells holding the 16 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 920:6487 (43.975, 144.375). Over 44 years there: absolute minimum -20.3 °C, 1st-percentile night -14.6 °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 12 distinct grid cells holding 16 of the 16 in-range records; extremes and elevation at the typical cell 920:6487 (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 44.00_144.375, lapse-corrected -84 m at 6.5 °C/km. Elevation: ETOPO 2022, 1 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.
NativeKuril Is., Japan · 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 marker43.918, 144.438 · in the densest population, 38 records (86% of those in range)
Kew's description“perennial or tuberous geophyte” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 44 georeferenced records inside the native range; the climate across the range on the 16 of them placed to within 10 km; the map shows only the 31 openly licensed ones, which alone would put the marker 20 km away. 28 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 of the 44 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Hemerocallis yezoensis, photograph 1did not loadHemerocallis yezoensis, photograph 2did not loadHemerocallis yezoensis, photograph 3did not loadHemerocallis yezoensis, photograph 4did not loadHemerocallis yezoensis, photograph 5did not loadHemerocallis yezoensis, photograph 6did not load

Photographs: (c) Rajan Rao, some rights reserved (CC BY); Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons (5).

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

Primula modesta Primula modesta Primulaceae Photo: CC BY, Hector MonteroLigularia hodgsonii Ligularia hodgsonii Asteraceae Photo: CC BY, Илья РуденкоArabis stelleri Arabis stelleri Coastal rockcress Photo: CC BY, りなべるPhedimus kamtschaticus Phedimus kamtschaticus Kamchatka Stonecrop Photo: CC BY, georges3Artemisia schmidtiana Artemisia schmidtiana Angel's-hair Photo: CC BY, Saryu Mae 前 朝琉Hylotelephium cauticola Hylotelephium cauticola Cliff stonecrop Photo: CC BY, Eleftherios Katsillis

Other Hemerocallis 11 in the reference

Hemerocallis citrina Hemerocallis citrina Citron day-lily Photo: CC BY, ippanjinHemerocallis dumortieri Hemerocallis dumortieri Dumortier's day-lily Photo: CC BY, Adam Mark Lucas-Krol Hemerocallis forrestii Asphodelaceae Hemerocallis fulva Hemerocallis fulva Orange day-lily Photo: CC0, author not statedHemerocallis hakuunensis Hemerocallis hakuunensis Baekunsan daylily Photo: CC BY, Martin KalfatovicHemerocallis lilioasphodelus Hemerocallis lilioasphodelus Yellow day-lily Photo: CC0, author not statedHemerocallis middendorffii Hemerocallis middendorffii Amur day-lily Photo: CC BY, Urgamal MagsarHemerocallis minor Hemerocallis minor Small daylily Photo: CC BY, ivansemenkov Hemerocallis multiflora Many-flower day-lily Hemerocallis nana Asphodelaceae Hemerocallis thunbergii Hemerocallis thunbergii Asphodelaceae Photo: CC BY, Epibase

Names & registers

Also known as Hemerocallis flava var. yezoensis; Hemerocallis lilioasphodelus var. yezoensis. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Asphodelaceae
Described by
H.Hara
Native to
Kuril Is., Japan
Wild records
44 in range · 31 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
Habitat climate climate answeredasked 2026-10-22
Daily extremes (NASA POWER) climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 44.00_144.375, lapse-corrected -84 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 2026-10-22none of the photographs on this page is credited to GBIF: those shown are other sources', and GBIF's were the same photographs or were set aside by the photograph rules
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 15 datasets via GBIF.org; each carries its own licence.

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