Example ⟳ +
An example collection, so you can see what this page does. Nothing added here is kept: leaving deletes it.
Juglans major; photograph (c) L. Reid, some rights reserved (CC BY) CC BY(c) L. Reid, some rights reserved (CC BY) · observed growing wild · 2026-09-01

Juglans major (Torr.) A.Heller

Arizona walnut; Arizona black walnut; New Mexico walnut

Juglandaceae · Oklahoma, Arizona +7

Add one to my plants
Sow seed
Juglans major, photograph (c) Jo Roberts, some rights reserved (CC BY)Juglans major, photograph (c) Jo Roberts, some rights reserved (CC BY)Juglans major, photograph (c) Jo Roberts, some rights reserved (CC BY)Juglans major, photograph (c) Jo Roberts, some rights reserved (CC BY)Juglans major, photograph (c) L. Reid, some rights reserved (CC BY)Juglans major, photograph (c) L. Reid, some rights reserved (CC BY) 78 photographs ›
Habitat figures
Cold floor (1 night in 100)
-4.7°C
Record low -10.5 °C in 44 years, at a typical spot in the range NASA POWER
Warmest month, mean daily high
31°C
Jun and Jul at the habitat CHELSA
Rain a year (median across the range)
527mm
9 months of 25 mm or more in the median year CHELSA
Open-sky light
21–52DLI
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
A rainy season, December to February and July to October, neither the cool nor the warm half of the year. rain rule, CHELSA
Northern hemisphere unless you set your site. The chart is in the habitat's months.

Summary

Juglans major (literally, the larger walnut), also known as Arizona walnut, is a walnut tree which grows to 50 ft tall (15 m) with a DBH of up to 0.61 metres (2 ft) at elevations of 300–2,130 m (1,000–7,000 ft) in Texas, Oklahoma, New Mexico, Arizona, and Utah. It also occurs in Mexico as far south as Guerrero. Common names include Arizona black walnut (as it belongs to the "black walnuts" section Juglans sect. Rhysocaryon), and the Spanish name nogal cimarrón (cimarron walnut).

Quoted from Wikipedia, "Juglans major", CC BY-SA 4.0.

Cultivation

Seasons

The rain rule reads a rainy season with no name: 70% of the median year's rain (366 mm of 476 mm) falls in December to February and July to October, whose mean temperature, 15.9 °C, is within half a degree of the year's, 16.4 °C, so it is neither the cooler nor the warmer part of the year. Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: January to April and June to August.

Rain

476 mm in the median year at the habitat, 366 mm of it December to February and July to October. Wettest month August at 83 mm, driest month May at 15 mm. Across the grid cells of the range the year's total runs 370 mm to 930 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 527 mm, is the year's rain at the top of the page; the 476 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: 21 to 52 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 18, the highest 90th-percentile month 54).

Warmth and air
Temperature

Coldest: the 1st-percentile night over 44 years at a typical spot in the range is -4.7 °C, the absolute minimum -10.5 °C, 1,819 frost nights in 44 years, 41.3 a year (NASA POWER daily minima). Warmest: the 99th-percentile day is 39.4 °C. Monthly means: the coldest month's mean nightly low 1.2 °C in January (across the grid cells of the range -3.9 °C to 6.3 °C), the warmest month's mean daily high 31.4 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: -4.7 °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: 40 to 53% 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 +143 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 Juglans major through the yearWarmest months June and July, mean daily high 31 °C; coldest month January, mean nightly low 1.2 °C; 476 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°50°frost39.4° 99th-percentile day, NASA POWER-10.5° lowest night in 44 years, NASA POWER°C · day and nightcold quarter0255075100125150mm rainDLI 21–52RH 40–53%JanFebMarAprMayJunJulAugSepOctNovDec
day night rain medians and 10th–90th percentile across 647 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 °C14 / 8–1916 / 10–2119 / 13–2424 / 18–2728 / 23–3131 / 26–3431 / 26–3430 / 25–3428 / 23–3124 / 19–2719 / 13–2214 / 8–20
Night °C1 / -4–62 / -3–85 / -1–118 / 3–1513 / 8–1917 / 12–2219 / 14–2318 / 14–2316 / 11–2111 / 6–165 / 0–111 / -4–7
Rain mm37 / 19–5734 / 15–5830 / 9–7117 / 9–6215 / 7–9921 / 7–12081 / 50–15083 / 52–14156 / 38–10236 / 26–10527 / 15–6839 / 16–59
DLI23 / 19–2729 / 24–3338 / 29–4247 / 36–4951 / 37–5352 / 41–5445 / 41–4741 / 39–4338 / 33–3932 / 26–3425 / 20–2921 / 18–26
RH %51 / 47–5749 / 46–5746 / 43–5742 / 38–5741 / 35–6040 / 34–6050 / 44–5953 / 48–5949 / 45–5947 / 43–5848 / 44–5850 / 47–58
How this section is made
Each figure is the median across the 647 grid cells holding the 1169 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 1147:1384 (32.625, -110.775). Over 44 years there: absolute minimum -10.5 °C, 1st-percentile night -4.7 °C, 99th-percentile day 39.4 °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 647 distinct grid cells holding 1169 of the 1169 in-range records; extremes and elevation at the typical cell 1147:1384 (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 32.50_-110.625, lapse-corrected +143 m at 6.5 °C/km. Elevation: ETOPO 2022, 1321 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.
NativeOklahoma, Arizona, New Mexico, Texas, Mexico Central, Mexico Northeast, Mexico Gulf, Mexico Northwest, Mexico Southwest · introduced: North Caucasus, Transcaucasus · 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 marker32.013, -110.625 · in the densest population, 1005 records (63% of those in range)
Kew's description“tree” · “temperate” · quoted from WCVP, RBG Kew (CC BY 4.0); not derived here
Evidence usedThe map marker rests on all 1593 georeferenced records inside the native range; the climate across the range on the 1169 of them placed to within 10 km; the map shows only the 760 openly licensed ones, which alone would put the marker 15 km away. 10 records outside the WCVP native range not used. 424 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 1593 in-range records; it decides nothing. Records outside the native range, living specimens and records marked introduced are not used; which records count.

Photographs

Juglans major, photograph 1did not loadJuglans major, photograph 2did not loadJuglans major, photograph 3did not loadJuglans major, photograph 4did not loadJuglans major, photograph 5did not loadJuglans major, photograph 6did not load

Photographs: (c) Jo Roberts, some rights reserved (CC BY) (4); (c) L. Reid, some rights reserved (CC BY) (2).

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

Ipomoea cristulata Ipomoea cristulata Trans-Pecos morning-glory Photo: CC BY, John ThomlinsonQuercus oblongifolia Quercus oblongifolia Mexican blue oak Photo: CC BY-SA, M. Socorro González ElizondoEchinocereus rigidissimus Echinocereus rigidissimus Cactaceae Photo: CC BY, Rachel StringhamMimosa dysocarpa Mimosa dysocarpa Velvetpod mimosa Photo: CC BY, John ThomlinsonEchinocereus arizonicus Echinocereus arizonicus Arizona hedgehog cactus Photo: CC BY, Zihao WangTagetes lemmonii Tagetes lemmonii Lemmon's marigold Photo: CC BY, Sue Carnahan

Other Juglans 14 in the reference

Juglans australis Juglans australis Argentine walnut Photo: CC BY, aacocucciJuglans × bixbyi Juglans × bixbyi Bixby's walnut Photo: CC BY-SA, Douglas GoldmanJuglans californica Juglans californica Southern California black walnut Photo: CC BY, klickloJuglans cinerea Juglans cinerea Butternut Photo: CC BY, treelogicalJuglans hindsii Juglans hindsii Northern California black walnut Photo: CC BY, Irina Mitine Juglans hopeiensis Hebei walnut Juglans jamaicensis Juglans jamaicensis West Indian walnut Photo: CC BY, J. L. Gómez-HechavarríaJuglans mandshurica Juglans mandshurica Manchurian walnut Photo: CC BY, Maria GalkinaJuglans microcarpa Juglans microcarpa Little walnut Photo: CC BY, Sam KieschnickJuglans mollis Juglans mollis Mexican walnut Photo: CC BY, Cody HinchliffJuglans neotropica Juglans neotropica Andean walnut Photo: CC BY, GERMAN LEONEL SARMIENTO CRUZJuglans nigra Juglans nigra Black walnut Photo: CC BY, Sandy Wolkenberg all 15 ›

Names & registers

Also known as Juglans elaeopyren; Juglans major var. glabrata; Juglans microcarpa subsp. major; Juglans microcarpa var. major; Juglans rupestris var. major. (GBIF Backbone)

GBIFPOWOIPNIWFOWikidataWikipediaiNaturalist

The record

Family
Juglandaceae
Described by
(Torr.) A.Heller
Native to
Oklahoma, Arizona, New Mexico +6
Wild records
1593 in range · 760 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; 38 records within 1 km of a botanic garden, herbarium or zoo left out (34 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 32.50_-110.625, lapse-corrected +143 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 83 datasets via GBIF.org; each carries its own licence.

Cultifolio

Opening your plants…