Hydrangea serrata (Thunb.) Ser.
Mountain Hydrangea, tea of heaven
Every figure on this page is derived from public data by a stated rule and says its source; nothing here is written by a person or a model, except the Wikipedia passage, which is quoted and marked as such. How it is made.
Summary
Hydrangea serrata is a species of flowering plant in the family Hydrangeaceae, native to mountainous regions of Korea and Japan. Common names include mountain hydrangea and tea of heaven. Growing to 1.2 m (4 ft) tall and broad, it is a deciduous shrub with oval leaves and panicles of blue and pink flowers in summer and autumn (fall). It is widely cultivated as an attractive ornamental shrub throughout the world in areas with suitable climate and soil.
Text from Wikipedia, “Hydrangea serrata”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.
About the genus · Hydrangea
Hydrangea is a genus of more than 70 species of flowering plants native to Asia and the Americas. Hydrangea is also used as the common name for the genus; some are also often called hortensia. The genus was first described from Virginia in North America, but by far the greatest species diversity is in eastern Asia, notably China, Korea, and Japan. More on Wikipedia ›
The opening of Wikipedia, “Hydrangea”, CC BY-SA 4.0, quoted as written.
At a glance
Also known as Hortensia japonica (Siebold) H.Ohba & S.Akiyama; Hortensia serrata (Thunb.) H.Ohba & S.Akiyama; Hortensia serrata f. belladonna (Kitam.) H.Ohba & S.Akiyama; Hortensia serrata f. plenidecuris H.Ohba & S.Akiyama; Hortensia serrata f. prolifera (Regel) H.Ohba & S.Akiyama and 45 more.
Cultivation
Grouped as a temperate garden plant by the genus Hydrangea, which is reliably one kind of plant (archetype table). The table holds no figure for this group, which spans too much for one minimum; the cold floor is the habitat's alone, and no prose comes from the table.
Its year Rain rule: a summer growing season, March and May to October in the northern hemisphere (March and May to October at the habitat, northern).
This species’ habitat figures, and what two fixed rules read from them.
The rain rule reads a summer growing season: 70% of the year's rain (1526 mm of 2074 mm) falls in March and May to October, warmer than the year (wet-season mean 16.5 °C against a yearly mean of 11.1 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to April and September.
Read from the median year of CHELSA monthly rainfall and mean temperature across the envelope cells: 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 gives a season to reverse. A reading of the curves, not an observation of the plant.
Rain Habitat rain 2074 mm a year, wettest July at 290 mm, driest December at 78 mm (habitat calendar, northern hemisphere).
This species’ habitat figures, with their source.
2074 mm a year at the habitat, 1526 mm of it March and May to October. Wettest month July at 290 mm, driest December at 78 mm. Across the envelope cells the year's total runs 1433 mm to 3236 mm (10th to 90th percentile of each cell's own year) (median year across the envelope cells, CHELSA; habitat calendar, northern hemisphere).
CHELSA monthly precipitation, median year across the envelope cells. The rain that falls where the species is recorded; nothing about how the plant takes water.
Light Open sky over the habitat: 15 to 35 mol/m²/day.
This species’ habitat figures, with their source.
Open sky over the habitat: 15 to 35 mol/m²/day across the year (daily light integral, median year across the envelope cells, CHELSA; the lowest 10th-percentile month across the cells is 11, the highest 90th-percentile month 37).
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.
Warmth and air Cold floor -5.1 °C (1st-percentile habitat night, NASA POWER).
This species’ habitat figures, with their source.
Coldest: the 1st-percentile night over 44 years at the typical cell is -5.1 °C, the absolute minimum -10.9 °C, about 87 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 28.0 °C. Monthly means: coldest night -6.2 °C in January (across the envelope cells -12.1 °C to 0.3 °C), warmest day 26.2 °C in August (median year across the envelope cells, CHELSA). Cold floor: -5.1 °C, which is the 1st-percentile night over 44 years at the typical cell (NASA POWER).
NASA POWER daily minima and maxima 1981–2024 at the typical cell, lapse-corrected to its elevation; CHELSA monthly means, median year across the envelope cells, CHELSA. The cold floor is the figure named in its sentence. Not a measured survival limit for any plant in a pot.
Relative humidity at the habitat: 59 to 68% across the year (monthly means, median year across the envelope cells, CHELSA). A figure about the air, saying nothing about how the plant takes water.
CHELSA relative humidity, median year across the envelope cells.
The figures the cards read from are in Climate below, and where they came from in Natural habitat.
Climate across the habitat
Figures by month
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day °C | 2 / -4–7 | 3 / -3–8 | 7 / 1–11 | 14 / 8–17 | 18 / 14–21 | 22 / 18–24 | 25 / 21–28 | 26 / 23–29 | 22 / 18–25 | 17 / 12–20 | 11 / 6–15 | 5 / -1–10 |
| Night °C | -6 / -12–0 | -6 / -11–1 | -2 / -7–4 | 4 / -1–9 | 9 / 5–13 | 14 / 10–18 | 18 / 14–22 | 19 / 15–23 | 15 / 11–20 | 9 / 5–14 | 3 / -2–8 | -3 / -9–3 |
| Rain mm | 90 / 41–293 | 104 / 48–202 | 151 / 76–225 | 147 / 89–222 | 174 / 113–264 | 225 / 150–354 | 290 / 173–428 | 237 / 151–371 | 265 / 190–366 | 184 / 101–258 | 129 / 62–281 | 78 / 35–292 |
| DLI | 17 / 13–19 | 22 / 19–24 | 27 / 25–30 | 33 / 31–35 | 35 / 32–37 | 32 / 28–35 | 31 / 28–33 | 32 / 28–34 | 25 / 23–27 | 21 / 19–24 | 17 / 13–19 | 15 / 11–17 |
| RH % | 61 / 55–68 | 60 / 55–66 | 60 / 56–63 | 59 / 56–61 | 61 / 58–63 | 65 / 62–68 | 68 / 65–71 | 67 / 63–70 | 65 / 62–68 | 62 / 59–65 | 61 / 58–65 | 60 / 56–67 |
Each figure is the median across the 1128 grid cells holding the 1486 in-range records, with the 10th–90th percentile span across those cells after the slash where it differs. Extremes and elevation were read at the typical cell 1094:6286 (35.275, 134.325). Over 44 years there: absolute minimum -10.9 °C, 1st-percentile night -5.1 °C, 99th-percentile day 28.0 °C. Normals: CHELSA V2.1 1981–2010 climatology, 0.05° cells (each the mean of ~36 1 km pixels). Envelope: median and 10th–90th percentile of each month across the 1128 distinct grid cells holding the 1486 in-range records; extremes and elevation at the typical cell 1094:6286 (its coldest month's mean night nearest the median across cells); its position is the cell centre. Extremes: NASA POWER (MERRA-2) daily 1981–2024, cell 35.50_134.375, lapse-corrected +556 m at 6.5 °C/km. Elevation: ETOPO 2022, 798 m (cell mean).
Natural habitat
Photographs
Photographs: W Rao, CC BY, iNaturalist via GBIF (2); Marco Mussita, CC BY, iNaturalist via GBIF (2); Miriam Gargiulo, CC BY-SA, via GBIF; 岸本年郎, CC BY, iNaturalist via GBIF (2); WATANABE Hitoshi 渡辺仁, CC BY, iNaturalist via GBIF.
Photographs: iNaturalist did not answer when this page was built; what is shown came from the sources that did.
Papers naming this species
Works whose title or abstract names Hydrangea serrata, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.
Related
Similar habitat climate the 6 species whose habitat climate is nearest this one's: mean day and night, month by month, and rain on a log scale, in calendar order, so a habitat with the same seasons six months out is far, not near. Nothing else counts: not range, not family.
Hydrangea paniculata Panicle Hydrangea
Acer palmatum Japanese Maple
Magnolia kobus Kobus Magnolia
Hosta sieboldiana Siebold's Plantain Lily
Hosta sieboldii Siebold's Plantain Lily
Petasites japonicus Creamy ButterburOther Hydrangea 5 in the reference
Hydrangea arborescens Smooth Hydrangea
Hydrangea macrophylla Bigleaf Hydrangea Hydrangea paniculata Panicle Hydrangea
Hydrangea petiolaris Climbing hydrangea
Hydrangea quercifolia oak-leaf hydrangea History & registers
Where this page came from built 2026-09-20 · dossier v2 · node
gbif.species answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)gbif.synonyms answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)gbif.vernacular answeredcarried from build of 2026-09-19 (offline re-derivation; the backbone was not asked)wcvp.distribution answeredgbif.occurrences answeredGBIF occurrence download https://doi.org/10.15468/dl.3h4zamclimate answeredwikidata answeredcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)wikipedia answeredcarried from build of 2026-09-19; this build: skippedinat.taxon not askedinat.photos.wild not askedcarried from build of 2026-09-19 (rederive); that build: not asked: 9 wild photographs already from the GBIF downloadinat.photos.cultivated nothing to reportcarried from build of 2026-09-19 (rederive); that build: filled 2026-09-20commons nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)gbif.media answeredopenalex answeredcarried from build of 2026-09-19; this build: skippedEvery upstream is recorded as having answered, reported nothing, or refused. Only “nothing to report” is ever shown as an absence. Records came from 86 datasets via GBIF.org; each carries its own licence.