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Trillium albidum; photograph author not stated, no rights reserved CC0author not stated, no rights reserved · observed growing wild · 2026-08-22

Trillium albidum J.D.Freeman

Giant white wakerobin; Freeman's Trillium; Sweet Trillium; White Toadshade

Melanthiaceae · Oregon, Washington +1

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Trillium albidum, photograph author not stated, no rights reservedTrillium albidum, photograph author not stated, no rights reservedTrillium albidum, photograph author not stated, no rights reservedTrillium albidum, photograph author not stated, no rights reservedTrillium albidum, photograph author not stated, no rights reservedTrillium albidum, photograph author not stated, no rights reserved 101 photographs ›
Habitat figures
Cold floor (1 night in 100)
-3.7°C
Record low -17.3 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
28°C
Jul and Aug at the habitat CHELSA
Rain a year (median across the range)
1,379mm
10 months of 25 mm or more in the median year CHELSA
Open-sky light
10–50DLI
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 winters: the rain comes November to March, read as a winter growing season. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Trillium albidum is a species of flowering plant in the bunchflower family Melanthiaceae. It is the only trillium characterized by a stalkless white flower. The species is endemic to the western United States, ranging from central California through Oregon to southwestern Washington. In the San Francisco Bay Area, it is often confused with a white-flowered form of Trillium chloropetalum. More on Wikipedia ›

Quoted from Wikipedia, "Trillium albidum", CC BY-SA 4.0.

About the genus · Trillium

Trillium is a genus of about fifty flowering plant species in the family Melanthiaceae. Trillium species are native to temperate regions of North America and Asia, with the greatest diversity of species found in the southern Appalachian Mountains in the southeastern United States.

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

Cultivation

Seasons

The rain rule reads a winter growing season: 70% of the median year's rain (1,004 mm of 1,343 mm) falls in November to March, cooler than the year (wet-season mean 6.2 °C against a yearly mean of 11.5 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: May to September.

Rain

1,343 mm in the median year at the habitat, 1,004 mm of it November to March. Wettest month December at 249 mm, driest month July at 10 mm. Across the grid cells of the range the year's total runs 880 mm to 1,867 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 1,379 mm, is the year's rain at the top of the page; the 1,343 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 50 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 7, the highest 90th-percentile month 53).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -3.7 °C, the absolute minimum -17.3 °C, 1,205 frost nights in 44 years, 27.4 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 35.6 °C. Monthly means: the coldest month's mean nightly low 1.2 °C in December (across the grid cells of the range -2.8 °C to 4.6 °C), the warmest month's mean daily high 27.9 °C in August (median year across the grid cells of the range, CHELSA). Cold floor: -3.7 °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: 54 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 -249 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 Trillium albidum through the yearWarmest months July and August, mean daily high 28 °C; coldest month December, mean nightly low 1.2 °C; 1,343 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.-20°-10°0°10°20°30°40°frost35.6° 99th-percentile day, NASA POWER-17.3° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0100200300400mm rainDLI 10–50RH 54–64%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 425 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 °C9 / 6–1311 / 7–1413 / 10–1616 / 13–1919 / 17–2323 / 21–2828 / 25–3128 / 25–3125 / 22–2819 / 17–2312 / 10–168 / 5–13
Night °C2 / -3–42 / -3–53 / -1–65 / 1–88 / 4–1010 / 8–1213 / 11–1413 / 11–1411 / 9–137 / 5–114 / 0–71 / -3–5
Rain mm213 / 142–318179 / 120–266153 / 104–23698 / 58–14169 / 36–9629 / 7–6110 / 1–1712 / 3–1925 / 8–5196 / 53–127210 / 124–272249 / 174–377
DLI12 / 8–1518 / 14–2026 / 21–3035 / 29–4042 / 36–4748 / 40–5250 / 44–5345 / 39–4835 / 30–3823 / 18–2713 / 9–1710 / 7–13
RH %64 / 57–6962 / 58–6662 / 57–6560 / 54–6358 / 51–6156 / 47–6054 / 43–5754 / 43–5855 / 45–5857 / 49–6263 / 55–6863 / 57–69
How this section is made
Each figure is the median across the 425 grid cells holding the 1080 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 934:1133 (43.275, -123.325). Over 44 years there: absolute minimum -17.3 °C, 1st-percentile night -3.7 °C, 99th-percentile day 35.6 °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 425 distinct grid cells holding 1080 of the 1080 in-range records; extremes and elevation at the typical cell 934:1133 (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 43.50_-123.125, lapse-corrected -249 m at 6.5 °C/km. Elevation: ETOPO 2022, 276 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.
NativeOregon, Washington, California · 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 marker44.533, -123.198 · in the densest population, 926 records (70% of those in range)
Kew's description“rhizomatous geophyte” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1332 georeferenced records inside the native range; the climate across the range on the 1080 of them placed to within 10 km; the map shows only the 230 openly licensed ones, which alone would put the marker 9 km away. 20 records outside the WCVP native range not used. 252 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 1332 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Trillium albidum, photograph 1did not loadTrillium albidum, photograph 2did not loadTrillium albidum, photograph 3did not loadTrillium albidum, photograph 4did not loadTrillium albidum, photograph 5did not loadTrillium albidum, 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.

Calochortus tolmiei Calochortus tolmiei Tolmie star-tulip Photo: CC BY, Alexander WentworthHosackia pinnata Hosackia pinnata Meadow bird's-foot trefoil Photo: CC BY, My-Lan LeSidalcea asprella Sidalcea asprella Harsh Checkermallow Photo: CC0, author not statedEryngium petiolatum Eryngium petiolatum Oregon Coyote-Thistle Photo: CC0, author not statedCarex feta Carex feta Green-sheathed sedge Photo: CC BY, Gabriel Campbell-MartinezPlagiobothrys figuratus Plagiobothrys figuratus Rough popcornflower Photo: CC BY, Alex Wilson

Other Trillium 39 in the reference

Trillium angustipetalum Trillium angustipetalum Narrowpetal wakerobin Photo: CC BY, Barry Langdon-LassagneTrillium apetalon Trillium apetalon Melanthiaceae Photo: CC BY, Kristof ZyskowskiTrillium camschatcense Trillium camschatcense Kamchatka trillium Photo: CC BY, Kristof ZyskowskiTrillium catesbaei Trillium catesbaei Bashful wakerobin Photo: CC BY, willingardenTrillium cernuum Trillium cernuum Whip-poor-will flower Photo: CC BY, Dustin SniderTrillium chloropetalum Trillium chloropetalum Giant trillium Photo: CC0, author not statedTrillium cuneatum Trillium cuneatum Little sweet Betsy Photo: CC BY, Joseph FeltsTrillium decipiens Trillium decipiens Chattahoochee River wakerobin Photo: CC BY, Brandon CorderTrillium decumbens Trillium decumbens Decumbent Trillium Photo: CC BY-SA, Turner BrockmanTrillium discolor Trillium discolor Mottled wakerobin Photo: CC BY, Rachel StepekTrillium erectum Trillium erectum Red trillium Photo: CC BY, Evan M. RaskinTrillium flexipes Trillium flexipes Drooping trillium Photo: CC BY, Chris Stahl all 40 ›

Names & registers

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Melanthiaceae
Described by
J.D.Freeman
Native to
Oregon, Washington, California
Wild records
1332 in range · 230 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; 153 records within 1 km of a botanic garden, herbarium or zoo left out (125 at a botanic garden or arboretum, 28 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 43.50_-123.125, lapse-corrected -249 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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