Is the Cherry Blossom Japan’s National Flower? A Flower No Law Names and the Somei-yoshino Spread from One Tree

Every spring, when the cherry trees burst into bloom, someone is bound to say it: “The cherry blossom is Japan’s national flower, isn’t it?” We hear it so often that we rarely stop to question it. Yet the one Japanese statute that directly defines national symbols, the 1999 Act on the National Flag and Anthem, specifies only two things: the flag and the anthem. It says nothing about a flower. So how did the cherry blossom become “Japan’s flower”? Where did the Somei-yoshino trees that line today’s streets come from, and how are they related to the king cherry of Hallasan on Jeju Island? Let us take it step by step, through law, history and genetics.

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Japan Has No National Flower Defined by Law

The Act on the National Flag and Anthem, promulgated on 13 August 1999, consists of just two articles. Article 1 says that the national flag shall be the Hinomaru, and Article 2 that the national anthem shall be Kimigayo (Japan’s e-Gov law database). No provision naming a national flower appears in this act or in any other. The Japanese outlet Nippon.com likewise explains that Japan has no legally defined national flower or national seal. The cherry blossom, as the flower people hold dearest, and the chrysanthemum, as the imperial crest, have each simply come to represent Japan.

If anything, the flower closer to official documents is the chrysanthemum. The sixteen-petaled chrysanthemum design is said to have become the imperial symbol when Emperor Go-Toba (reigned 1183–1198) adopted it as his personal emblem (Nippon.com). An 1869 proclamation of the Daijō-kan (Grand Council of State) fixed the “sixteen-petaled double chrysanthemum” as the imperial crest, and in 1871 its use by anyone outside the imperial family was banned. The Imperial Household Ceremonial Ordinance of 1926 codified it again (Japanese Wikipedia, “菊花紋章”). The emblem on the cover of today’s Japanese passport is a simplified “sixteen-petaled single chrysanthemum”, and the emblem the Japanese government uses for itself is not the chrysanthemum at all but a paulownia crest (五七桐) (Wikipedia, “Imperial Seal of Japan”). Even the chrysanthemum came from China as a medicinal plant during the Nara period (710–794) (Nippon.com). A “national flower” here is a title created by long custom and use, not by law.

The First Beloved Blossom Was the Plum, Not the Cherry

The impression that the cherry blossom has symbolized Japan since time immemorial is also not quite right. Hanami (花見), the custom of enjoying flowers, began in the Nara period, and the flower people first admired was the plum, a taste shaped by Chinese culture (Wikipedia, “Hanami”). The eighth-century poetry anthology Man’yōshū (萬葉集) contains 43 poems about cherry blossoms but about 110 about plum blossoms (Japanese Wikipedia, “花見”). We look at the plum blossom itself in Plum Blossoms in Snow: Fragrance Chemistry and the Defenses of Unripe Ume.

The focus shifted to the cherry blossom in the Heian period (794–1185). The chronicle Nihon Kōki (日本後紀) records that in 812 Emperor Saga held a flower banquet, the “Kaen no sechi” (花宴の節), at the Kyoto garden of Shinsen-en (神泉苑), and this is regarded as the first recorded cherry-blossom viewing. From 831 it became a regular court event hosted by the emperor (Japanese Wikipedia, “花見”). The cherry blossom became Japan’s representative flower through more than a thousand years of accumulated culture, not by legal decree.

Somei-yoshino Began as a Single Tree Where Two Species Met

The cherry most widely planted across Japan today is the Somei-yoshino (染井吉野). It is a hybrid of two different species. Its mother line is the Edo-higan, and its father line is the Oshima cherry, native to the Izu Islands (Cho & Kim 2019). The Somei-yoshino genome, sequenced by Japanese researchers in 2019, spans about 690.1 million base pairs and contains 95,076 genes. The team also read the two parental chromosome sets separately, resolving about 350.1 million base pairs from the Edo-higan side and about 340.0 million from the Oshima side (Shirasawa et al. 2019).

The tree was born in Edo, in the village of Somei (染井), home to many nurserymen, in what is now the Komagome area of Toshima, Tokyo. When it arose is debated. One study dates it to an artificial cross in the early eighteenth century (Iwasaki 1991), while other accounts place it at the end of the Edo period. Among the oldest planting records that can be confirmed is one from the Koishikawa Botanical Garden in 1775 (Japanese Wikipedia, “ソメイヨシノ”). At first it was sold as the “Yoshino cherry”, borrowing the name of Mount Yoshino, a famous cherry-viewing spot. Then, in 1900, Fujino Yorinaga surveyed the cherries of Ueno Park, showed that this tree differed from the mountain cherries of Mount Yoshino, and named it “Somei-yoshino”; the following year Matsumura Jinzō published the scientific name Prunus yedoensis (same source).

A Clone Spread by Grafting Instead of Seed

The Somei-yoshino is a self-incompatible interspecific hybrid: it cannot set seed with its own pollen (Shirasawa et al. 2024). Self-incompatibility is a finely designed mechanism that stops a tree from fertilizing itself, so that it shares pollen with other individuals and keeps its genetic diversity. Even when pollen from another cherry produces seed, the tree that grows from it is a new individual with a different father, not a Somei-yoshino. That is why people have multiplied this cultivar by grafting rather than by seed. A DNA fingerprinting analysis in 1995 confirmed that the Somei-yoshino is a clone descended from one single tree (Japanese Wikipedia, “ソメイヨシノ”).

Because trees with the same genotype respond to temperature in much the same way, this turns out to be useful. Japan’s Meteorological Agency uses the Somei-yoshino as its sample tree for cherry-blossom flowering at most observation sites, the exceptions being Okinawa and Amami (Taiwan cherry, hikanzakura) and some sites in Hokkaido (Sargent’s cherry, ezoyamazakura) (Japan Meteorological Agency). Since individual trees differ little in flowering date under the same conditions, linking regional flowering dates to draw a “cherry-blossom front” works well. We explain why a whole city’s cherries open together in Why a Whole City’s Cherry Blossoms Open in the Same Week.

That does not mean every Somei-yoshino has exactly the same DNA, letter for letter. In 2024, a team led by Shirasawa in Japan analyzed 46 Somei-yoshino trees from across the country and found 684 single-nucleotide mutations. Of these, 71 appeared in more than one tree, because each grafted branch carried its mutations along with it. Grouping the trees by these shared mutations sorted the 46 trees into eight groups, and 36 of them fell into four of those groups. All four trees sampled in Ueno Park, Tokyo, belonged to those four groups, and the researchers concluded that one of them is the closest to the original ancestor (Shirasawa et al. 2024). Small mutations ended up serving as a family tree that confirms the trees spread from a single individual.

Jeju’s King Cherry Arose Separately in the Forests of Hallasan

Now to Korea’s king cherry. In 1908 the French missionary Father Émile Taquet collected cherry specimens on Hallasan, and in 1912 the German botanist Koehne reported them as a variety under the Somei-yoshino’s scientific name, Prunus yedoensis var. nudiflora (Cho & Kim 2019). Because the name tied it to the Somei-yoshino, a misconception arose that the Somei-yoshino grows wild on Jeju. In 1916 the English plant explorer E. H. Wilson examined the Jeju specimen and wrote that the evidence was inconclusive for settling where the Somei-yoshino came from, and in 1932 the Japanese botanist Koidzumi Gen’ichi argued that the Somei-yoshino originated on Jeju (Wikipedia, “Prunus × nudiflora”). It is worth noting that the scholar who put forward the Jeju-origin theory in academic terms was Japanese.

This long-standing question was answered by twenty-first-century molecular research. In 2014 Cho and colleagues presented the first convincing evidence that Jeju’s wild king cherry is a hybrid of two species. The mother side was Prunus spachiana f. ascendens (Edo-higan), while the father side was narrowed to the cherry and mountain-cherry group (P. serrulata/P. sargentii) without being pinned down exactly. The same paper also raised the possibility that the cultivated Somei-yoshino came from the wild Jeju population (Cho et al. 2014). In 2018 Baek and colleagues sequenced the genome of the wild king cherry and reported that it is a first-generation hybrid between Edo-higan (mother side) and P. jamasakura, a mountain cherry growing in the same forests (father side), clearly distinct from the Somei-yoshino (Baek et al. 2018).

In 2019 Cho and Kim widened the scope, collected many more individuals, and reanalyzed them with four different molecular markers. The conclusion was clear. Jeju’s wild king cherry arose from repeated natural crosses, in both directions, between Edo-higan (mother side) and the cherry lineage (father side), both growing in the same forests. The Somei-yoshino, by contrast, is a cultivar born of a single artificial cross between cultivated Edo-higan and Oshima cherry. The two trees are separate taxa that arose by different processes (Cho & Kim 2019). With more data, the same researchers corrected the “Jeju origin” possibility they had left open in 2014.

Wild king cherries on Hallasan are rare. A survey of the Hallasan area from March 2015 to October 2016 found 194 trees at 173 locations, growing between 165 and 853 meters above sea level (Wikipedia, “Prunus × nudiflora”). The king cherry habitat at Bonggae-dong, Jeju City, was designated a Natural Monument in 1964 (Korea Heritage Portal).

The Names Are Still Being Settled

The scientific names have been changing along with this research. In 2016 Katsuki and colleagues proposed the name Cerasus × nudiflora for Jeju’s wild king cherry, distinguishing it from the Somei-yoshino (Wikipedia, “Prunus × nudiflora”). Plants of the World Online (POWO), the world plant list of the Royal Botanic Gardens, Kew, currently lists Prunus × nudiflora (Koehne) Koidz. as the accepted name of a hybrid native to Korea, and classifies Prunus × yedoensis Matsum. separately as an artificial hybrid (Kew POWO). In Korea, the Korea National Arboretum, citing comparative genome research, gave the wild Jeju trees the Korean name “Jeju king cherry” (Jeju wangbeonnamu) and decided to call the cultivated king cherries planted along streets simply “king cherry” (wangbeonnamu). But because Korean experts disagree about how to interpret the trees’ origin, the Korean name was put up for review again in 2022, and some proposed sequencing the genomes of every wild tree on Jeju (Halla Ilbo 2022). The naming question, in other words, is not yet settled.

There is no need to read this story as a contest over which country has the “original”. What the research shows is simple. The Jeju king cherry is a wild hybrid that arose on its own on Korean soil; the Somei-yoshino is a single cultivar made by the gardeners of Edo; and the two are different trees that share only their mother lineage.

Behind a single cherry blossom lies a story far more intricate than the familiar saying. A “national flower” that was never set down in law, a love that moved over from the plum, a clone spread from one tree along with the tiny mutations that revealed its family tree, and a tree that arose separately in the forests of Hallasan. The living things God made are always woven more finely than the names people hastily give them. Next spring, when the words “the cherry blossom is Japan’s national flower” come to mind beneath the blossoms, why not pause and take one more look at where that tree came from?

Correction · 2026-10-03 We replaced two photos that did not match their captions (a 1931 film lobby card presented as the Jeju king cherry, and a cross-section of plum wood presented as white plum blossoms) with photos of the actual subjects, and added a lineage comparison diagram and further photos. We updated the account of how Kew’s POWO treats the scientific names to match its current records (the Somei-yoshino as an artificial hybrid, the Jeju king cherry accepted as Prunus × nudiflora), and corrected the statement that the Somei-yoshino cannot set seed at all. We added the legal history of the chrysanthemum crest and the passport emblem, the research history of the Jeju-origin theory (Koidzumi’s 1932 claim, the possibility raised in 2014, and its correction in 2019), and the differing views on when the Somei-yoshino arose, and we removed statements we could not verify.

References

• Act on the National Flag and Anthem (Act No. 127 of 1999) — Japan e-Gov Law Search
• The Chrysanthemum: Flower of Emperors — Nippon.com
• Japanese Wikipedia: 菊花紋章 (Chrysanthemum crest)
• Wikipedia: Imperial Seal of Japan
• Wikipedia: Hanami
• Japanese Wikipedia: 花見 (Hanami)
• Japanese Wikipedia: ソメイヨシノ (Somei-yoshino)
• Shirasawa et al. (2019), Phased genome sequence of ‘Somei-Yoshino’ — DNA Research
• Shirasawa et al. (2024), Propagation path of ‘Somei-Yoshino’ traced by somatic mutations — DNA Research
• Cherry blossom flowering observations — Japan Meteorological Agency (in Japanese)
• Cho et al. (2014), Hybrid origin of wild Prunus yedoensis from Jeju Island — American Journal of Botany
• Baek et al. (2018), Draft genome sequence of wild Prunus yedoensis — Genome Biology
• Cho & Kim (2019), Independent origin of wild and cultivated flowering cherry — Frontiers in Plant Science
• Wikipedia: Prunus × nudiflora
• Prunus × nudiflora (Koehne) Koidz. — Kew POWO
• Prunus × yedoensis Matsum. — Kew POWO
• Jeju Bonggae-dong King Cherry Tree Habitat — Korea Heritage Portal (in Korean)
• The Korean name “Jeju king cherry” to be reviewed again — Halla Ilbo, 5 May 2022 (in Korean)

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