Wildspecies of cherry tree are widely distributed, mainly in the Northern Hemisphere.[3][4][5] They are common in East Asia, especially inJapan, where they have been cultivated, producing many varieties.[6]: 40–42, 160–161
Most of the ornamental cherry trees planted in parks and other places for viewing arecultivars developed for ornamental purposes from various wildspecies. In order to create a cultivar suitable for viewing, a wild species with characteristics suitable for viewing is needed.Prunus speciosa (Oshima cherry), which is endemic to Japan, produces many large flowers, is fragrant, easily mutates into double flowers and grows rapidly. As a result, various cultivars, known as theCerasus Sato-zakura Group, have been produced since the 14th century and continue to contribute greatly to the development ofhanami (flower viewing) culture.[1]: 27, 89–91 [6]: 160–161 From the modern period, cultivars are mainly propagated bygrafting, which quickly produces cherry trees with the same genetic characteristics as the original individuals, and which are excellent to look at.[6]: 89–91
The Japanese wordsakura (桜;Japanese pronunciation:[sa.kɯ.ɾa][7]) can mean either the tree or its flowers (see桜).[8] The cherry blossom is considered thenational flower of Japan, and is central to the custom of hanami.[9]
Sakura trees are often calledJapanese cherry in English.[10] (This is also acommon name forPrunus serrulata.[11]) The cultivation of ornamental cherry trees began to spread inEurope and theUnited States in the early 20th century, particularly after Japan presented trees to the United States as a token of friendship in 1912.[1]: 119–123 British plant collectorCollingwood Ingram conducted important studies of Japanese cherry trees after theFirst World War.[12]
Classification
Classifying cherry trees is often confusing, since they are relatively prone to mutation and have diverse flowers and characteristics, and manyvarieties (a sub-classification of species), hybrids between species, and cultivars exist. Researchers have assigned different scientific names to the same type of cherry tree throughout different periods.[1]: 32–37
In Europe and North America, ornamental cherry trees are classified under the subgenusCerasus ("true cherries"), within the genusPrunus.Cerasus consists of about 100 species of cherry tree, but does not includebush cherries,bird cherries, orcherry laurels (other non-Cerasus species inPrunus areplums,peaches,apricots, andalmonds).Cerasus was originally named as agenus in 1700 byde Tournefort. In 1753,Linnaeus combined it with several other groupings to form a largerPrunus genus.Cerasus was later converted into asection and then asubgenus, this system becoming widely accepted, but some botanists resurrected it as a genus instead.[13] In China and Russia, where there are many more wild cherry species than in Europe,Cerasus continues to be used as a genus.[1]: 14–18
In Japan, ornamental cherry trees were traditionally classified in the genusPrunus, as in Europe and North America, but after a 1992 paper by Hideaki Ohba of the University of Tokyo, classification in the genusCerasus became more common.[1]: 14–18 This means that (for example) thescientific nameCerasus incisa is now used in Japan instead ofPrunus incisa.[14]
A culture ofplum blossom viewing has existed in mainland China since ancient times, and although cherry trees have many wild species, most of them had small flowers, and the distribution of wild cherry trees with large flowers suitable for cherry blossom viewing was limited.[6]: 160–161 In Europe and North America, there were few cherry species with characteristics suitable for cherry blossom viewing.[1]: 122 In Japan, on the other hand, thePrunus speciosa (Oshima cherry) andPrunus jamasakura (Yamazakura), which have large flowers suitable for cherry blossom viewing and tend to grow into large trees, were distributed over a fairly large area of the country and were close to people's living areas. The development of cherry blossom viewing, and the production of cultivars, is therefore considered to have taken place primarily in Japan.[6]: 160–161
Because cherry trees have mutable traits, manycultivars have been created for cherry blossom viewing, especially in Japan. Since theHeian period, the Japanese have produced cultivars by selecting superior or mutant trees from among the natural crossings of wild cherry trees. They were also produced by crossing trees artificially and then breeding them bygrafting andcutting. Oshima, Yamazakura,Prunus pendula f.ascendens (syn,Prunus itosakura, Edo higan), and other varieties which grow naturally in Japan, mutate easily. The Oshima cherry, which is anendemic species in Japan, tends to mutate into adouble-flowered tree, grows quickly, has many large flowers, and has a strong fragrance. Due to these favorable characteristics, the Oshima cherry has been used as a base for many Sakura cultivars (called theSato-zakura Group). Two such cultivars are theYoshino cherry andKanzan; Yoshino cherries are actively planted in Asian countries, and Kanzan is actively planted in Western countries.[1]: 86–95, 106, 166–168 [15][16][6]: 40–42
"Hanami" is the many centuries-old practice of holding feasts or parties under bloomingsakura (桜 or櫻;さくら orサクラ) orume (梅;うめ) trees. During theNara period (710–794), when the custom is said to have begun, it wasume blossoms that people admired. By theHeian period (794–1185), however, cherry blossoms were attracting more attention, and'hanami' was synonymous with'sakura'.[17] From then on, in bothwaka andhaiku, "flowers" (花,hana) meant "cherry blossoms," as implied by one ofIzumi Shikibu's poems.[18] The custom was originally limited to the elite of the Imperial Court but soon spread tosamurai society and, by theEdo period, to the common people as well.Tokugawa Yoshimune planted areas of cherry blossom trees to encourage this. Under thesakura trees, people held cheerful feasts where they ate, and dranksake.[1]: 2–7, 156–160
Prunus itosakura (syn.Prunus subhirtella, Edo higan) is a wild species that grows slowly. However, it has the longest life span among cherry trees and is easy to grow into large trees. For this reason, there are many large, old specimens of this species in Japan. They are often regarded as sacred and have become landmarks that symbolizeShinto shrines, Buddhist temples, and local areas. For example,Jindai-zakura [ja], which is around 2,000 years old,Usuzumi-zakura [ja], which is around 1,500 years old, andDaigo-zakura [ja], which is around 1,000 years old, are famous for their age.[1]: 178–182
'Kanzan' is adouble-flowered cultivar developed in the Edo period. It has 20 to 50 petals in a flower.[1]: 93, 103–104
In the Edo period, variousdouble-flowered cultivars were produced and planted on the banks of rivers, in Buddhist temples, in Shinto shrines, and indaimyo gardens in urban areas such asEdo; the common people living in urban areas could enjoy them. Books from the period record more than 200 varieties of cherry blossoms and mention many varieties that are currently known, such as'Kanzan'. However, this situation was limited to urban areas, and the main objects of hanami across the country were still wild species such asPrunus jamasakura (Yamazakura) [ja] and Oshima cherry.[1]
Since Japan was modernized in theMeiji period, theYoshino cherry has spread throughout Japan, and it has become the main object of hanami.[1]: 2–7, 156–160 Various other cultivars were cut down one after another during changes related to the rapid modernization of cities, such as the reclamation of waterways and the demolition ofdaimyo gardens. The gardener Takagi Magoemon and the village mayor of Kohoku Village, Shimizu Kengo, were concerned about this situation and preserved a few by planting a row of cherry trees, of various cultivars, along theArakawa River bank. In Kyoto, Sano Toemon XIV, a gardener, collected various cultivars and propagated them. After World War II, these cultivars were inherited by theNational Institute of Genetics,Tama Forest Science Garden and the Flower Association of Japan, and from the 1960s onwards were again used for hanami.[1]: 115–119
Every year, theJapanese Meteorological Agency (JMA) and the public track thesakura zensen ("cherry blossom front") as it moves northward up the archipelago with the approach of warmer weather, via nightly forecasts following the weather segment of news programs.[19][20] Since 2009, tracking of thesakura zensen has been largely taken over by private forecasting companies, with the JMA switching to focus only on data collection that than forecasting.[21] The blossoming begins inOkinawa in January and typically reachesKyoto and Tokyo at the beginning of April, though recent years have trended towards earlier flowerings near the end of March.[22] It proceeds northward and into areas of higher altitude, arriving inHokkaido a few weeks later. Japanese locals, in addition to overseas tourists, pay close attention to these forecasts.[21]
Most Japanese schools and public buildings have cherry blossom trees planted outside of them. Since the fiscal and school years both begin in April, in many parts ofHonshu the first day of work or school coincides with the cherry blossom season. However, while most cherry blossom trees bloom in the spring, there are also lesser-known winter cherry blossoms (fuyuzakura in Japanese) that bloom between October and December.[23]
The Japan Cherry Blossom Association has published a list of Japan's Top 100 Cherry Blossom Spots (日本さくら名所100選 [ja]),[24] with at least one location in every prefecture.
Blooming season
Yoshino cherry, a cultivar propagated throughgrafting, consistently reaches full bloom simultaneously between individuals if under the same environmental conditions.
Many cherry species and cultivars bloom between March and April in the Northern Hemisphere. Wild cherry trees, even if they are the same species, differ genetically from one individual to another. Even if they are planted in the same area, there is some variation in the time when they reach full bloom. In contrast, cultivars are clones propagated by grafting or cutting, so each tree of the same cultivar planted in the same area will come into full bloom all at once due to their genetic similarity.[25]
Some wild species, such asEdo higan and the cultivars developed from them, are in full bloom before the leaves open.Yoshino cherry became popular for cherry-blossom viewing because of these characteristics of simultaneous flowering and blooming before the leaves open; it also bears many flowers and grows into a large tree. Many cultivars of theSato-zakura group, which were developed from complex interspecific hybrids based on Oshima cherry, are often used for ornamental purposes. They generally reach full bloom a few days to two weeks after Yoshino cherry does.[1]: 40–56
Impacts of climate change
The flowering time of cherry trees is thought to be affected by global warming and theheat island effect ofurbanization. According to the record of full bloom dates ofPrunus jamasakura (Yamazakura) inKyoto, Japan, which has been recorded for about 1200 years, the time of full bloom was relatively stable from 812 to the 1800s. After that, the time of full color rapidly became earlier, and in 2021, the earliest full bloom date in 1200 years was recorded. The average peak bloom day in the 1850s was around April 17, but by the 2020s, it was April 5; the average temperature rose by about 3.4 °C (6.1 °F) during this time. According to the record of full bloom dates of the Yoshino cherry in theTidal Basin inWashington, D.C., the bloom date was April 5 in 1921, but it was March 31 in 2021. These records are consistent with the history of rapid increases in global mean temperature since the mid-1800s.[26][27]
Japanese cherry trees grown in the Southern Hemisphere bloom at a different time of the year. For example, in Australia, while the trees in theCowra Japanese Garden bloom in late September to mid-October, the Sydney cherry blossom festival is in late August.[28][29]
There's an escalating concern ofclimate change as it poses a threat to sakura cultivars, given that they are highly susceptible to shifts in temperature and weather fluctuations. The changes, driven by climate change including warmer temperatures and earlier starts to springtime, may disrupt the timing of their blooms and potentially lead to reduced flowering and cultural significance.[30]
In 2023, it has been observed in China that cherry blossoms have reached their peak bloom weeks earlier than they previously had a few decades ago. Similarly, data from Kyoto, Japan, and Washington, D.C., United States, also indicated that blooming periods are occurring earlier in those locations as well.[31]
Although precise forecasting is generally challenging, AI predictions fromJapan Meteorological Agency, have suggested that without substantial efforts to rein in climate change, the Somei-Yoshino cherry tree variety could face significant challenges and even the risk of disappearing entirely from certain parts of Japan, including Miyazaki, Nagasaki, and Kagoshima prefectures in the Kyushu region by 2100.[32]
Cherry blossoms are a frequent topic inwaka composition, where they commonly symbolize impermanence.[33] Due to their characteristic of bloomingen masse, cherry blossoms are considered an enduring metaphor for the ephemeral nature of life.[34] Cherry blossoms frequently appear inJapanese art,manga,anime, and film, as well as stage set designs for musical performances. There is at least one popularfolk song, originally meant for theshakuhachi (bamboo flute), titled "Sakura", in addition to several laterpop songs bearing the name. The flower is also used on all manner of historical and contemporary consumer goods, includingkimonos,[35] stationery,[36] anddishware.[37]
Mono no aware
The traditional symbolism of cherry blossoms as a metaphor for the ephemeral nature of life is associated with the influence ofShinto,[38] embodied in the concept ofmono no aware (物の哀れ)[a] (the pathos of things).[39] The connection between cherry blossoms andmono no aware dates back to 18th-century scholarMotoori Norinaga.[39] The transience of the blossoms, their beauty, and their volatility have often been associated with mortality[34] and the graceful and ready acceptance of destiny and karma.
DuringWorld War II, cherry blossoms were used as a symbol to motivate the Japanese people and stoke nationalism and militarism.[41] The Japanese proverbhana wa sakuragi, hito wa bushi ("the best blossom is the cherry blossom, the best man is a warrior") was evoked in theImperial Japanese Army as a motivation during the war.[42] Even before the war, cherry blossoms were used in propaganda to inspire the "Japanese spirit", as in the "Song of Young Japan", exulting in "warriors" who were "ready like the myriad cherry blossoms to scatter".[43] In 1894,Sasaki Nobutsuna composed a poem,Shina seibatsu no uta (The Song of the Conquest of the Chinese) to coincide with theFirst Sino-Japanese War. The poem compares falling cherry blossoms to the sacrifice of Japanese soldiers who fall in battles for their country and emperor.[44][45] In 1932,Akiko Yosano's poetry urged Japanese soldiers to endure suffering in China and compared the dead soldiers to cherry blossoms.[46] Arguments that the plans for theBattle of Leyte Gulf, involving all Japanese ships, would expose Japan to danger if they failed were countered with the plea that the Navy be permitted to "bloom as flowers of death".[47] The last message of the forces onPeleliu was "Sakura, Sakura".[48] Japanese pilots would paint sakura flowers on the sides of their planes before embarking on a suicide mission, or even take branches of the trees with them on their missions.[41] A cherry blossom painted on the side of a bomber symbolized the intensity and ephemerality of life;[49] in this way, falling cherry petals came to represent the sacrifice of youth in suicide missions to honor the emperor.[41][50] The firstkamikaze unit had a subunit calledYamazakura, or wild cherry blossom.[50] The Japanese government encouraged the people to believe that the souls of downed warriors were reincarnated in the blossoms.[41]
Cherry blossoms have been used symbolically in Japanese sports; theJapan national rugby union team has used the flower as an emblem on its uniforms since the team's first international matches in the 1930s, depicted as a "bud, half-open and full-bloomed".[52] The team is known as the "Brave Blossoms" (ブレイブ・ブロッサムズ), and has had their current logo since 1952.[51] The cherry blossom is also seen in the logo of theJapan Cricket Association[53] and theJapan national American football team.[54][55]
Cherry blossoms are a prevalent symbol inirezumi, the traditional art of Japanese tattoos. In this art form, cherry blossoms are often combined with other classic Japanese symbols likekoi fish,dragons, ortigers.[56]
The cherry blossom remains symbolic today. It was used for theTokyo 2020 Paralympics mascot,Someity.[57] It is also a common way to indicate the start of spring, such as in theAnimal Crossing series of video games, where many of the game's trees are flowering cherries.[58]
Japan has a wide diversity of cherry trees, including hundreds ofcultivars.[61] By one classification method, there are more than 600 cultivars in Japan,[62][63] while theTokyo Shimbun claims that there are 800.[64] According to the results ofDNA analysis of 215 cultivars carried out by Japan's Forestry and Forest Products Research Institute in 2014, many of the cultivars that have spread around the world are hybrids produced by crossingOshima cherry andPrunus jamasakura (Yamazakura) with various wild species.[15][16] Among these cultivars, theSato-zakura Group and many other cultivars have a large number of petals, and the representative cultivar isPrunus serrulata 'Kanzan'.[1]: 137
The following species, hybrids, andvarieties are used forSakura cultivars:[65][66]
The most popular cherry blossom cultivar in Japan is'Somei-yoshino' (Yoshino cherry). Its flowers are nearly pure white, tinged with the palest pink, especially near the stem. They bloom and usually fall within a week before the leaves come out. Therefore, the trees look nearly white from top to bottom. The cultivar takes its name from the village of Somei, which is now part ofToshima in Tokyo. It was developed in the mid- to late-19th century, at the end of theEdo period and the beginning of theMeiji period. The 'Somei-yoshino' is so widely associated with cherry blossoms thatjidaigeki and other works of fiction often show the trees being cultivated in theEdo period or earlier, although such depictions are anachronisms.[1]: 40–45
''Prunus'' × ''kanzakura'' 'Kawazu-zakura' [ja] is a representative cultivar that blooms before the arrival of spring. It is a natural hybrid between the Oshima cherry andPrunus campanulata and is characterized by deep pink petals. Wild cherry trees usually do not bloom in cold seasons because they cannot produce offspring if they bloom before spring, when pollinating insects become active. However, it is thought that 'Kawazu-zakura' blooms earlier becausePrunus campanulata fromOkinawa, which did not originally grow naturally inHonshu, was crossed with the Oshima cherry. In wild species, flowering before spring is a disadvantageous feature of selection; in cultivars such as 'Kawazu-zakura', early flowering and flower characteristics are preferred, and they are propagated by grafting.[1]: 98–100
Cherry trees are generally classified by species and cultivar, but in Japan they are also classified using names based on the characteristics of the flowers and trees. Cherry trees with more petals than the ordinary five are classified asyae-zakura (double-flowered sakura), and those with drooping branches are classified asshidare-zakura, or weeping cherry. Mostyae-zakura andshidare-zakura are cultivars. Famousshidare-zakura cultivars include 'Shidare-zakura', 'Beni-shidare', and 'Yae-beni-shidare', all derived from the wild speciesPrunus itosakura (syn,Prunus subhirtella or Edo higan).[1]: 86–87
In 2007,Riken produced a new cultivar named 'Nishina zao' by irradiating cherry trees with aheavy-ion beam. This cultivar is amutation of the green-petaled''Prunus serrulata'' 'Gioiko' (Gyoiko) [ja]; it is characterized by its pale yellow-green-white flowers when it blooms and pale yellow-pink flowers when they fall. Riken produced the cultivars 'Nishina otome' (blooms in both spring and autumn, or year-round in a greenhouse), 'Nishina haruka' (larger flowers), and 'Nishina komachi' ('lantern-like' flowers that remain partially closed) in the same way.[76][77]
In the present day, ornamental cherry blossom trees are distributed and cultivated worldwide.[80] While flowering cherry trees were historically present in Europe, North America, Philippines, and China,[1]: 122 the practice of cultivating ornamental cherry trees was centered in Japan,[6]: 160–161 and many of thecultivars planted worldwide, such as that ofPrunus × yedoensis,[81] have been developed from Japanese hybrids.
The global distribution of ornamental cherry trees, along with flower viewing festivals orhanami, largely started in the early 20th century, often as gifts from Japan.[82][83][84] However, some regions have historically cultivated their own native species of flowering cherry trees, a notable variety of which is the Himalayan wild cherry treePrunus cerasoides.[85][86][87]
In 1975, three Japanese researchers proposed a theory that cherry trees originated in the Himalayan region and spread eastwards to reach Japan at a time before human civilisation, when the Japanese archipelago was connected to the Eurasian continent, and that cherry species differentiation was actively promoted in Japan.[91]
According to Masataka Somego, a professor atTokyo University of Agriculture, cherry trees originated 10 million years ago in what is now Nepal and later differentiated in the Japanese archipelago, giving rise to species unique to Japan.[92]
According to the Kazusa DNA Research Institute, detailed DNA research has shown that thePrunus itosakura and thePrunus speciosa, which is endemic to Japan, differentiated into independent species 5.52 million years ago.[93][94]
On the other hand, according to Ko Shimamoto, a professor atNara Institute of Science and Technology, modern theories based on detailed DNA research reject the theory that the Himalayan cherry tree is the root of the Japanese cherry tree, and the ancestor of the cherry tree is estimated to be a plant belonging to thePrunus grayana.[95]
According toHuffPost, it is a widely held consensus that the origin of the first cherry blossoms happened somewhere in the Himalayas, Eurasia but scholars posit that the blossoms may have reached Japan around several thousand years ago. In Japan, centuries of hybridization have brought about more than 300 varieties of the cherry blossom.[96]
Cherry blossoms and leaves are edible,[97] and both are used as food ingredients in Japan:
The blossoms are pickled in salt andumezu (ume vinegar),[98] and used for coaxing out flavor inwagashi, atraditional Japanese confectionery, oranpan, a Japanese sweetbun most-commonly filled withred bean paste.[99] The pickling method, known assakurazuke (桜漬け), is said to date back to the end of theEdo period,[100] though the general method of pickling vegetables in salt to producetsukemono has been known as early as theJōmon period.[101]
Salt-pickled blossoms in hot water are calledsakurayu[102] and drunk at festive events like weddings in place ofgreen tea.[100][103]
Cherry blossoms are used as a flavoring botanical in Japanese Rokugin.[104]
Toxicity
Cherry leaves and blossoms containcoumarin,[105][106] which is potentiallyhepatotoxic and is banned in high doses by theFood and Drug Administration.[107] However, coumarin has a desirable vanilla-like scent, and the salt curing process used prior to most culinary applications, which involves washing, drying, and salting the blossoms or leaves for a full day, reduces the concentration of coumarin to acceptable levels while preserving its scent.[97] Coumarin may also be isolated from the plant for use in perfumes,[108] pipetobacco, or as anadulterant in vanilla flavorings, though thetonka bean is a more common natural source of this chemical.[109]
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Vancouver Cherry Blossom Festival—Information about the 37,000 cherry trees in Greater Vancouver (Canada), What's in bloom now, Cherry Scout reports and maps, Cultivar identification.