Citrullus lanatus (watermelon)

Plate 1 figs. a–h · 8 separate observations

Citrullus lanatus, photographed by Agnes — fig. a Agnes, CC BY 4.0 / 2022-05-30 / obs. 202004013

Citrullus lanatus, photographed by Ellky Arteta Paredes — fig. b Ellky Arteta Paredes, CC BY 4.0 / obs. 193984345

Citrullus lanatus, photographed by Eduardo Luis Beltrocco — fig. c Eduardo Luis Beltrocco, CC BY 4.0 / obs. 178610861

Citrullus lanatus, photographed by Roman Luštrik — fig. e Roman Luštrik, CC BY 4.0 / obs. 158964975

Citrullus lanatus, photographed by Gabriel Mayrhofer — fig. f Gabriel Mayrhofer, CC0 1.0 / obs. 152235049

Citrullus lanatus, photographed by Michelle W. （鍾偉瑋） — fig. g Michelle W. （鍾偉瑋）, CC BY 4.0 / obs. 148705112

Citrullus lanatus, photographed by Zinogre — fig. h Zinogre, CC BY-SA 4.0 / obs. 144325786

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 4 botanical countries

Native distribution of Citrullus lanatus, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows.

Region	TDWG code	Continent
Egypt	EGY	AFRICA
Ethiopia	ETH
Libya	LBY
Sudan-South Sudan	SUD

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 96 in flower of 188 examined

60%

22%

80%

44%

60%

50%

43%

58%

48%

67%

17%

Proportion of examined Citrullus lanatus in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	3	5	60%	23% to 88%
Feb	2	9	22%	6% to 55%
Mar	3	4	too few examined
Apr	8	10	80%	49% to 94%
May	4	9	44%	19% to 73%
Jun	6	10	60%	31% to 83%
Jul	12	24	50%	31% to 69%
Aug	15	35	43%	28% to 59%
Sep	21	36	58%	42% to 73%
Oct	15	31	48%	32% to 65%
Nov	6	9	67%	35% to 88%
Dec	1	6	17%	3% to 56%

Peak flowering in Apr. Each bar is the share of Citrullus lanatus observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 96 of 188 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Where it actually grows measured, from 1,508 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-9.8 °C	6.0 °C	23.0 °C
Warmest month, mean daily high	22.8 °C	29.3 °C	35.9 °C
Annual rainfall	203 mm	848 mm	2,315 mm
Rainfall in the driest quarter	3 mm	100 mm	305 mm

It is found where winters bring hard frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,508 research-grade observations of Citrullus lanatus that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 57 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

Anguria citrullus (L.) Mill.
Citrullus afrorum Schrad.
Citrullus anguria (Duches.) Hara
Citrullus aquosus Schur
Citrullus battich Forssk.
Citrullus chodospermus Fal. & Dun.
Citrullus citrullus Small
Citrullus citrullus (L.) H.Karst.
Citrullus colocynthis var. capensis Alef.
Citrullus colocynthis var. lanatus (Thunb.) Matsum. & Nakai
Citrullus edulis Spach
Citrullus edulis Pangalo
Citrullus lanatus f. nigroseminius (Chakravarty) Maheshw.
Citrullus lanatus subsp. cordophanus Ter-Avan.
Citrullus lanatus subsp. mucosospermus Fursa
Citrullus lanatus var. afrorum (Alef.) Fosberg
Citrullus lanatus var. albidus (Chakravarty) Maheshw.
Citrullus lanatus var. caffrorum (Alef.) Fosberg
Citrullus lanatus var. capensis (Alef.) Fursa
Citrullus lanatus var. cordophanus (Ter-Avan.) Fursa
Citrullus lanatus var. fistulosus (Stocks) Babu
Citrullus lanatus var. lanatus
Citrullus lanatus var. minor (Chakravarty) Maheshw.
Citrullus lanatus var. oblongus (Chakravarty) Maheshw.

and 33 more.

Sourcesevery claim on this page

World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.