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Symphytum cordatum; photograph author not stated, no rights reserved CC0author not stated, no rights reserved · observed growing wild · 2026-05-03

Symphytum cordatum Waldst. & Kit. ex Willd.

Boraginaceae · Czechoslovakia, Poland +2

Cited as Kew's World Checklist cites it, Symphytum cordatum Waldst. & Kit. ex Willd.: GBIF's backbone key for this page carries the name with another author, Waldst. & Kit.

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Symphytum cordatum, photograph (c) Алла Козурак, some rights reserved (CC BY)Symphytum cordatum, photograph (c) Mike Grant, some rights reserved (CC BY)Symphytum cordatum, photograph (c) xulescu_g, some rights reserved (CC BY-SA)Symphytum cordatum, photograph author not stated, no rights reservedSymphytum cordatum, photograph author not stated, no rights reservedSymphytum cordatum, photograph author not stated, no rights reserved 54 photographs ›
Habitat figures
Cold floor (1 night in 100)
-19.0°C
Record low -30.1 °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)
984mm
12 months of 25 mm or more in the median year CHELSA
Open-sky light
5–33DLI
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.

About the genus · Symphytum

Symphytum is a genus of flowering plants in the borage family, Boraginaceae, known by the common name comfrey.

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

Cultivation

Seasons

The rain rule reads a summer growing season: 70% of the median year's rain (699 mm of 981 mm) falls in April to October, warmer than the year (wet-season mean 12.1 °C against a yearly mean of 6.4 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: October to April.

Rain

981 mm in the median year at the habitat, 699 mm of it April to October. Wettest month July at 134 mm, driest month February at 49 mm. Across the grid cells of the range the year's total runs 713 mm to 1,370 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 984 mm, is the year's rain at the top of the page; the 981 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: 5 to 33 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 5, 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 -19.0 °C, the absolute minimum -30.1 °C, 6,900 frost nights in 44 years, 156.8 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 28.2 °C. Monthly means: the coldest month's mean nightly low -7.6 °C in January (across the grid cells of the range -10.1 °C to -6.1 °C), the warmest month's mean daily high 20.4 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: -19.0 °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 +153 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 Symphytum cordatum through the yearWarmest months July and August, mean daily high 20 °C; coldest month January, mean nightly low -7.6 °C; 981 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.-40°-30°-20°-10°0°10°20°30°frost28.2° 99th-percentile day, NASA POWER-30.1° lowest night in 44 years, NASA POWER°C · day and nightcold quarter050100150200mm rainDLI 5–33RH 60–68%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 461 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-1 / -4–00 / -3–25 / 1–711 / 8–1316 / 13–1919 / 16–2120 / 18–2320 / 18–2316 / 13–1811 / 8–134 / 2–60 / -3–1
Night °C-8 / -10–-6-7 / -10–-6-4 / -7–-21 / -2–37 / 4–910 / 7–1212 / 9–1411 / 9–147 / 5–103 / 1–5-2 / -4–0-6 / -9–-5
Rain mm51 / 33–7949 / 35–7059 / 38–8769 / 50–94108 / 84–148125 / 96–171134 / 101–175106 / 80–13691 / 63–12366 / 47–10661 / 41–9262 / 40–98
DLI7 / 6–812 / 11–1420 / 18–2228 / 27–2932 / 31–3433 / 32–3532 / 31–3429 / 27–3120 / 19–2213 / 12–158 / 7–95 / 5–7
RH %67 / 64–7166 / 63–6963 / 61–6660 / 58–6361 / 59–6463 / 61–6663 / 61–6663 / 61–6564 / 62–6765 / 63–6867 / 64–7068 / 65–72
How this section is made
Each figure is the median across the 461 grid cells holding the 1107 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 816:4053 (49.175, 22.675). Over 44 years there: absolute minimum -30.1 °C, 1st-percentile night -19.0 °C, 99th-percentile day 28.2 °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 461 distinct grid cells holding 1107 of the 1107 in-range records; extremes and elevation at the typical cell 816:4053 (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 49.00_22.500, lapse-corrected +153 m at 6.5 °C/km. Elevation: ETOPO 2022, 680 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.
NativeCzechoslovakia, Poland, Romania, Ukraine · introduced: Germany · 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 marker49.405, 20.378 · in the densest population, 977 records (67% 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 1460 georeferenced records inside the native range; the climate across the range on the 1107 of them placed to within 10 km; the map shows only the 600 openly licensed ones, which alone would put the marker 339 km away. 7 records outside the WCVP native range not used. 353 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.
Other GBIF keysRecords also from GBIF's key 7377391 (Symphytum cordatum Waldst. & Kit. ex Willd.): Kew's file holds it as Symphytum cordatum Waldst. & Kit. ex Willd. (accepted); 900 records, from GBIF's search API on the day of the build.
How this section is made
The map marker: the openly licensed record nearest the middle of the densest 1° population of the 1460 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Symphytum cordatum, photograph 1did not loadSymphytum cordatum, photograph 2did not loadSymphytum cordatum, photograph 3did not loadSymphytum cordatum, photograph 4did not loadSymphytum cordatum, photograph 5did not loadSymphytum cordatum, photograph 6did not load

Photographs: (c) Алла Козурак, some rights reserved (CC BY); (c) Mike Grant, some rights reserved (CC BY); (c) xulescu_g, some rights reserved (CC BY-SA); author not stated, no rights reserved · CC0 (3).

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

Dianthus praecox Dianthus praecox Caryophyllaceae Photo: CC BY, Patrick HackerErysimum witmannii Erysimum witmannii Brassicaceae Photo: CC0, author not statedCampanula carpatica Campanula carpatica Tussock bellflower Photo: CC BY-SA, xulescu_gCrocus heuffelianus Crocus heuffelianus Iridaceae Photo: CC BY, Mike GrantGentianella praecox Gentianella praecox Gentianaceae Photo: CC BY, Vladimír FukaSenecio umbrosus Senecio umbrosus Asteraceae Photo: CC0, author not stated

Other Symphytum 9 in the reference

Symphytum asperum Symphytum asperum Prickly comfrey Photo: CC BY, Екатерина КравцоваSymphytum bulbosum Symphytum bulbosum Bulbous Comfrey Photo: CC BY-SA, Andrea MologniSymphytum caucasicum Symphytum caucasicum Caucasian comfrey Photo: CC0, author not statedSymphytum grandiflorum Symphytum grandiflorum Creeping comfrey Photo: CC BY, Наталья ПикаловаSymphytum officinale Symphytum officinale Common comfrey Photo: CC BY-SA, Douglas GoldmanSymphytum orientale Symphytum orientale White comfrey Photo: CC0, author not statedSymphytum tauricum Symphytum tauricum Crimean Comfrey Photo: CC BY, Viktor StrenadaSymphytum tuberosum Symphytum tuberosum Tuberous comfrey Photo: CC BY, Oleksandr ShynderSymphytum × uplandicum Symphytum × uplandicum Russian comfrey Photo: CC BY, guywallbanks

Names & registers

Also known as Symphytum cordifolium; Symphytum pannonicum. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataiNaturalist

The record

Family
Boraginaceae
Described by
Waldst. & Kit. ex Willd.
Native to
Czechoslovakia, Poland, Romania +1
Wild records
1460 in range · 600 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 2026-10-22GBIF's key 4067440 is Symphytum cordatum Waldst. & Kit.; the page links Kew's Symphytum cordatum Waldst. & Kit. ex Willd., and the name is cited as Kew cites it
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 answeredasked 2026-10-22GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 900 records of GBIF's key 7377391, Symphytum cordatum Waldst. & Kit. ex Willd. (Kew's file holds it as Symphytum cordatum Waldst. & Kit. ex Willd. (accepted)): GBIF occurrence search API; 33 records within 1 km of a botanic garden, herbarium or zoo left out (29 at a botanic garden or arboretum, 4 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 49.00_22.500, lapse-corrected +153 m at 6.5 °C/km
Wikidata wikidata answeredasked 2026-10-22
Wikipedia wikipedia nothing to reportasked 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 2026-10-22read from the page's key and its other keys: 3 from GBIF's key 7377391
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 44 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…