Species
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Symphyotrichum novi-belgii (L.) G.L.Nesom

Confused Michaelmas Daisy, Confused Michaelmas-daisy, Confused Michaelmas-daisy (EN), Longleaf Aster

Climate known 102 photographs
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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

Symphyotrichum novi-belgii, commonly called New York aster, is a species of flowering plant. It is the type species for Symphyotrichum, a genus in the family Asteraceae, whose species were once considered to be part of the genus Aster. Plants in both these genera are popularly known as Michaelmas daisy because they bloom around September 29, St. Michael’s Day.

Text from Wikipedia, “Symphyotrichum novi-belgii”, CC BY-SA 4.0, quoted as written. Kept separate from everything derived here.

About the genus · Symphyotrichum

Symphyotrichum is a genus of over 100 species and naturally occurring hybrids of herbaceous annual and perennial plants in the composite family, Asteraceae, most which were formerly treated within the genus Aster. The majority are endemic to North America, but several also occur in the West Indies, Central and South America, as well as one species in eastern Eurasia. Several species have been introduced to Europe as garden specimens, most notably New England aster and New York aster.

Text from Wikipedia, “Symphyotrichum”, CC BY-SA 4.0, quoted as written.

Family
Asteraceae
Described by
(L.) G.L.Nesom
Native to
Labrador, New Brunswick, Newfoundland +17
Wild records
380 in range· 159 open

At a glance

Warmest month
22°C
Jul, mean day; nights 15 °C (CHELSA)
Rain
1235mm/yr
12 wet months · peak Oct 113 mm (CHELSA)
Light
8–38DLI
mol/m²/day, winter to summer, open sky (CHELSA shortwave)
In short condensed by rule from the cultivation cards · not written by a person
Rain rule: no season, 70% of the rain takes 9 months (March and May to December in the northern hemisphere). Habitat rain 1235 mm a year, wettest October at 113 mm, driest February at 85 mm (habitat calendar, northern hemisphere). Open sky over the habitat: 8 to 38 mol/m²/day. Cold floor -15.2 °C (1st-percentile habitat night, NASA POWER).
Each sentence is one card's own one-line form, written by the same rule as the card (Its year, Rain, Light, Temperature); the note cannot say what a card does not. Months are given for the northern hemisphere (set your site in Settings to change this), and the habitat's own alongside. The cards · the figures.

Also known as Amellus divaricatus Gaterau; Amellus novae-belgii (L.) Opiz; Amellus novi-belgii (L.) Opiz; Asre longifollius Lam.; Aster adulterinus Willd. and 45 more.

Cultivation

Its year Rain rule: no season, 70% of the rain takes 9 months (March and May to December in the northern hemisphere).

This species’ habitat figures, and what two fixed rules read from them.

The rain rule reads no season: 70% of the year's rain (959 mm of 1235 mm) takes 9 months, March and May to December. Mean temperature moves 24.2 °C between the warmest and coldest month. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to June 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 1235 mm a year, wettest October at 113 mm, driest February at 85 mm (habitat calendar, northern hemisphere).

This species’ habitat figures, with their source.

1235 mm a year at the habitat, 959 mm of it March and May to December. Wettest month October at 113 mm, driest February at 85 mm. Across the envelope cells the year's total runs 1079 mm to 1565 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: 8 to 38 mol/m²/day.

This species’ habitat figures, with their source.

Open sky over the habitat: 8 to 38 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 6, the highest 90th-percentile month 40).

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 -15.2 °C (1st-percentile habitat night, NASA POWER).

This species’ habitat figures, with their source.

Temperature

Coldest: the 1st-percentile night over 44 years at the typical cell is -15.2 °C, the absolute minimum -23.8 °C, about 134 frost nights a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 26.9 °C. Monthly means: coldest night -9.4 °C in February (across the envelope cells -15.0 °C to -1.8 °C), warmest day 22.1 °C in July (median year across the envelope cells, CHELSA). Cold floor: -15.2 °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.

Humidity

Relative humidity at the habitat: 59 to 62% 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

Habitat climate through the yearMean day from -2 °C in Jan to 22 °C in Jul; mean night from -9 °C in Feb to 16 °C in Aug. The cold quarter, Jan to Mar, is the three months around the coldest night. 1235 mm of rain a year, most in Oct. The bands show the 10th to 90th percentile across 319 habitat cells. Over 44 years at the typical cell the absolute minimum was -23.8 °C and the 99th-percentile day 26.9 °C; neither is dated to a month. Beneath: daily light integral and relative humidity through the year, each on its own scale.-30°-20°-10°10°20°30°frost26.9° 99th-percentile day (undated)-23.8° lowest night in 44 yrs (undated)°C · day and nightcold quarter050100150200mm rainDLI 8–38RH 59–62 %JanFebMarAprMayJunJulAugSepOctNovDec
day night rain 10th–90th percentile across 319 habitat cells cold quarter: the three months around the coldest night extremes over 44 years at the typical cell, marked at the edge: undated DLI, mol/m²/dayRH %each on its own scale
Figures by month
JanFebMarAprMayJunJulAugSepOctNovDec
Day °C-2 / -8–4-1 / -7–52 / -2–97 / 3–1513 / 8–2019 / 13–2522 / 17–2822 / 18–2718 / 15–2312 / 8–177 / 2–122 / -4–7
Night °C-9 / -17–-2-9 / -15–-2-5 / -10–21 / -2–76 / 3–1211 / 8–1815 / 13–2116 / 13–2013 / 9–177 / 3–112 / -4–6-4 / -12–1
Rain mm92 / 75–14685 / 66–119105 / 71–13199 / 74–126101 / 87–119103 / 91–122105 / 90–127104 / 88–123105 / 93–131113 / 94–151113 / 88–160110 / 88–164
DLI10 / 8–1417 / 14–2025 / 23–2631 / 29–3335 / 33–3838 / 36–4037 / 34–4033 / 30–3525 / 21–2816 / 14–2110 / 8–148 / 6–12
RH %62 / 57–6561 / 56–6459 / 56–6359 / 56–6360 / 57–6461 / 58–6562 / 58–6762 / 59–6661 / 59–6460 / 58–6261 / 57–6361 / 57–65

Each figure is the median across the 319 grid cells holding the 358 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 882:2377 (45.875, -61.125). Over 44 years there: absolute minimum -23.8 °C, 1st-percentile night -15.2 °C, 99th-percentile day 26.9 °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 319 distinct grid cells holding the 358 in-range records; extremes and elevation at the typical cell 882:2377 (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 46.00_-61.250, lapse-corrected -48 m at 6.5 °C/km. Elevation: ETOPO 2022, 19 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 every in-range record's cell, not at the marker.
Openly licensed records inside the range, framed on where they fall.
NativeLabrador, New Brunswick, Newfoundland, Nova Scotia, Prince Edward I., Québec, Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode I., Vermont, West Virginia, Maryland, North Carolina, South Carolina, Virginia· introduced: Denmark, Great Britain, Ireland, Norway, Sweden, Austria, Belgium, Czechoslovakia, Germany, Hungary, Netherlands, Poland, Switzerland, France, Spain, Bulgaria, Greece, Italy, Romania, Yugoslavia, Belarus, Baltic States, Krym, Central European Russia, South European Russia, Ukraine, Buryatiya, West Siberia, Khabarovsk, Kuril Is., Primorye, Sakhalin, Turkmenistan, North Caucasus, Transcaucasus, East Aegean Is., Iraq, Korea, Jawa, New South Wales, Tasmania, Fiji, Marianas, Cuba, Dominican Republic
Kew's description“perennial” · “temperate”· quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Map marker45.311, -63.806 · in the densest population, 257 records (68% of those in range)
Evidence usedThe map marker and the climate envelope rest on all 380 georeferenced records inside the native range; the map shows only the 159 openly licensed ones, which alone would put the marker 239 km away. 1476 records outside the range (gardens, roadsides, misidentifications) ignored. 22 in-range records are placed to worse than 10 km and stay on the map but off the climate.
The map markerthe map marker: the openly licensed record nearest the middle of the densest 1° population inside the densest 4° block of the 380 in-range records; it decides nothing.

Photographs

Symphyotrichum novi-belgiiSymphyotrichum novi-belgiiSymphyotrichum novi-belgiiSymphyotrichum novi-belgiiSymphyotrichum novi-belgiiSymphyotrichum novi-belgiiSymphyotrichum novi-belgiiSymphyotrichum novi-belgii

Photographs: (c) Benoit Renaud, some rights reserved (CC BY) (5); (c) Alexis Tinker-Tsavalas, some rights reserved (CC BY); (c) Bryan Connolly, some rights reserved (CC BY) (2).

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 Symphyotrichum novi-belgii, most cited first, from OpenAlex (CC0). A mention, not a cultivation source: nothing on this page is drawn from them.

The effect of light colour and type of lamps on rooting and nutrient status in cuttings of Michaelmas daisy.
A. Schroeter-Zakrzewska, Tomasz Kleiber (2014) · Bulgarian Portal for Open Science
Stable colonization of native plants and early invaders by arbuscular mycorrhizal fungi after exposure to recent invaders from the Asteraceae family
Veronika Řezáčová, Milan Řezáč, Zuzana Líblová, Tereza Michalová (2021) · Invasive Plant Science and Management
New and rarely found in Buryatia taxa of adventive plants from the buffer zone of the Baikal Nature Reserve
Natalia S. Gamova, Sergey V. Dudov, А. В. Суткин, Alexandra S. Krasnopevtseva (2018) · Turczaninowia
First Report of Golovinomyces cichoracearum as the Causal Agent of Powdery Mildew on Symphyotrichum novi-belgii (Synonym Aster novi-belgii) in Denmark
Eline Kirk Mørk, Kell Kristiansen, Hans Jørgen Lyngs Jørgensen, Thomas Sundelin (2010) · Plant Disease
Response of Symphyotrichum novi-belgii and Dianthus chinensis L. to saline water irrigation in a coastal saline soil
Xiaobin Li, Yaohu Kang, Shuqin Wan, Xiulong Chen (2016) · Scientia Horticulturae
Vascular Plants of the Town of Belomorsk, Republic of Karelia
Алексей Васильевич Кравченко, В. В. Тимофеева, Оксана Алексеевна Рудковская, Маргарита Анатольевна Фадеева (2016) · Proceedings of the Karelian Research Centre of the Russian Academy of Sciences
First Report of Leaf Spots Caused by Alternaria arborescens on Symphyotrichum novi-belgii in Italy
A. Garibaldi, D. Bertetti, Slavica Matić, I. Luongo (2019) · Plant Disease
Floristic findings in alien flora of the Novosibirsk Region
Elena Yu. Zykova, Dmitry N. Shaulo, Tatyana V. Pankova, Оleg E. Kоsterin (2024) · Turczaninowia
Occurrence Download
GBIF.Org User (2024) · Global Biodiversity Information Facility

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.

Other Symphyotrichum 6 in the reference

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 answered
gbif.occurrences answeredGBIF occurrence download https://doi.org/10.15468/dl.3h4zam
climate answered
wikidata 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: skipped
inat.taxon not asked
inat.photos.wild answeredcarried from build of 2026-09-19; this build: skipped
inat.photos.cultivated nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
commons nothing to reportcarried from build of 2026-09-19 (rederive); that build: carried from build of 2026-09-19 (rederive)
gbif.media answered
openalex answeredcarried from build of 2026-09-19; this build: skipped

Every upstream is recorded as having answered, reported nothing, or refused. Only “nothing to report” is ever shown as an absence. Records came from 174 datasets via GBIF.org; each carries its own licence.