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Hedysarum sulphurescens; photograph author not stated, no rights reserved CC0author not stated, no rights reserved · observed growing wild · 2026-08-27

Hedysarum sulphurescens Rydb.

Yellow hedysarum; Sulphur hedysarum; Sulphur sweet-vetch; White sweetvetch

Fabaceae · Alberta, British Columbia +5

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Hedysarum sulphurescens, photograph author not stated, no rights reservedHedysarum sulphurescens, photograph author not stated, no rights reservedHedysarum sulphurescens, photograph author not stated, no rights reservedHedysarum sulphurescens, photograph author not stated, no rights reservedHedysarum sulphurescens, photograph author not stated, no rights reservedHedysarum sulphurescens, photograph author not stated, no rights reserved 66 photographs ›
Habitat figures
Cold floor (1 night in 100)
-29.3°C
Record low -44.6 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
20°C
Jul and Aug at the habitat CHELSA
Rain a year (median across the range)
818mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
7–44DLI
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

Hedysarum sulphurescens, the yellow sweetvetch or white sweetvetch, is a perennial herb species.

Quoted from Wikipedia, "Hedysarum sulphurescens", CC BY-SA 4.0.

Cultivation

Seasons

The rain rule reads no short rainy season: 70% of the median year's rain (626 mm of 814 mm) takes 8 months, April to November. Mean temperature moves 24.4 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: October to May.

Rain

814 mm in the median year at the habitat, 626 mm of it April to November. Wettest month June at 124 mm, driest month February at 40 mm. Across the grid cells of the range the year's total runs 546 mm to 1,275 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 818 mm, is the year's rain at the top of the page; the 814 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: 7 to 44 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 6, the highest 90th-percentile month 47).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -29.3 °C, the absolute minimum -44.6 °C, 11,404 frost nights in 44 years, 259.2 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 25.0 °C. Monthly means: the coldest month's mean nightly low -14.9 °C in December (across the grid cells of the range -18.9 °C to -10.7 °C), the warmest month's mean daily high 19.9 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: -29.3 °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: 53 to 64% 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 -10 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 Hedysarum sulphurescens through the yearWarmest months July and August, mean daily high 20 °C; coldest month December, mean nightly low -14.9 °C; 814 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.-60°-40°-20°0°20°40°frost25.0° 99th-percentile day, NASA POWER-44.6° lowest night in 44 years, NASA POWER°C · day and nightcold quarter050100150200mm rainDLI 7–44RH 53–64%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 547 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-6 / -10–-2-3 / -7–11 / -3–55 / 2–910 / 6–1515 / 12–1920 / 16–2420 / 16–2414 / 11–186 / 3–11-2 / -6–2-7 / -12–-3
Night °C-14 / -18–-10-13 / -16–-9-9 / -13–-6-5 / -8–-2-1 / -4–34 / 0–77 / 4–117 / 4–102 / -1–6-4 / -7–0-10 / -14–-6-15 / -19–-11
Rain mm49 / 19–11040 / 19–9151 / 31–9962 / 42–96103 / 69–144124 / 85–17580 / 51–11072 / 44–10570 / 44–10257 / 35–9758 / 25–12148 / 21–108
DLI9 / 7–1216 / 14–2026 / 23–2935 / 33–3941 / 39–4443 / 41–4644 / 41–4738 / 35–4128 / 26–3118 / 16–2110 / 8–137 / 6–10
RH %63 / 56–6961 / 56–6659 / 56–6356 / 54–6056 / 54–5856 / 53–5953 / 48–5653 / 48–5655 / 51–5858 / 54–6263 / 56–6964 / 56–70
How this section is made
Each figure is the median across the 547 grid cells holding the 1304 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 899:1401 (45.025, -109.925). Over 44 years there: absolute minimum -44.6 °C, 1st-percentile night -29.3 °C, 99th-percentile day 25.0 °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 547 distinct grid cells holding 1304 of the 1304 in-range records; extremes and elevation at the typical cell 899:1401 (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 45.00_-110.000, lapse-corrected -10 m at 6.5 °C/km. Elevation: ETOPO 2022, 2604 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.
NativeAlberta, British Columbia, Idaho, Montana, Oregon, Washington, Wyoming · 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 marker50.608, -114.936 · in the densest population, 914 records (62% of those in range)
Kew's description“perennial” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1480 georeferenced records inside the native range; the climate across the range on the 1304 of them placed to within 10 km; the map shows only the 482 openly licensed ones, which alone would put the marker 172 km away. 176 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 1480 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Hedysarum sulphurescens, photograph 1did not loadHedysarum sulphurescens, photograph 2did not loadHedysarum sulphurescens, photograph 3did not loadHedysarum sulphurescens, photograph 4did not loadHedysarum sulphurescens, photograph 5did not loadHedysarum sulphurescens, photograph 6did not load

Photographs: author not stated, no rights reserved · CC0 (6).

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

Aquilegia jonesii Aquilegia jonesii Jones' columbine Photo: CC0, author not statedAquilegia flavescens Aquilegia flavescens Yellow columbine Photo: CC BY, Logan JonesPolemonium pulcherrimum Polemonium pulcherrimum Showy Jacob's-ladder Photo: CC BY, Darrin LeBlancTelesonix heucheriformis Telesonix heucheriformis Heuchera-like brookfoam Photo: CC BY, Kerstin ReifenrathEremogone capillaris Eremogone capillaris Slender mountain sandwort Photo: CC BY, Matt BergerArtemisia michauxiana Artemisia michauxiana Michaux's wormwood Photo: CC BY, Daughter Dad

Other Hedysarum 7 in the reference

Hedysarum alpinum Hedysarum alpinum Alpine sweetvetch Photo: CC0, author not statedHedysarum boreale Hedysarum boreale Northern sweet-vetch Photo: CC BY, Peter L AchuffHedysarum caucasicum Hedysarum caucasicum Fabaceae Photo: CC BY, Dmitriy BochkovHedysarum hedysaroides Hedysarum hedysaroides Alpine French-honeysuckle Photo: CC BY, Katrin SimonHedysarum neglectum Hedysarum neglectum Fabaceae Photo: CC BY, Alexander DubyninHedysarum occidentale Hedysarum occidentale Western sweet-vetch Photo: CC BY, John BrewHedysarum vicioides Hedysarum vicioides Fabaceae Photo: CC BY, 岸本年郎

Names & registers

Also known as Hedysarum albiflorum; Hedysarum boreale var. albiflorum; Hedysarum boreale var. flavescens; Hedysarum flavescens; Hedysarum sulfureum. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Fabaceae
Described by
Rydb.
Native to
Alberta, British Columbia, Idaho +4
Wild records
1480 in range · 482 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 45.00_-110.000, lapse-corrected -10 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 40 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…