Why Most Cherry Trees in Japan Are Clones

Behind the famous pink clouds of spring is a single hybrid tree, copied by grafting for generations into millions of living duplicates.

Published October 21, 2026 at 11:46 PM JST | By Tokyo Paul

Quick answer: The most familiar cherry tree in Japan, Somei Yoshino, is a clone. It is a hybrid that cannot grow true from seed, so every tree comes from a graft taken from another tree, and all trace back to one original plant from the Edo period. That shared genetics is why whole cities bloom within days of each other.

Visitors who stand under a canopy of pale blossoms in Tokyo, Kyoto or Hirosaki are usually looking at the same tree, repeated thousands of times. This surprises many people, because cherry blossoms feel so natural and wild. The explanation is a mix of garden history, plant biology and a very practical technique that gardeners have used for centuries. This guide explains where the tree came from, why it must be copied rather than sown, how it spread across the country, and what it means for the way Japan watches spring arrive.

The short story of a single tree

Somei Yoshino is the variety most people mean when they say cherry blossoms in Japan. Its flowers are nearly white with a faint pink tint, and they open before the leaves appear, which gives the trees their cloud-like look. Research summaries describe it as a single hybrid that arose once and has since been multiplied by vegetative propagation. In other words, there is no large population of separate Somei Yoshino individuals with different genes. There is one genetic identity that exists in a vast number of bodies.

A 1995 DNA fingerprinting study concluded that the hybrid had originated only once and then spread across Japan through cuttings and grafts rather than seeds. A tree identified as one of the clones can therefore be compared to a photocopy of a photocopy: the pattern is the same, even if the paper is new. One Tokyo source describes the variety as making up roughly 80 percent of the country's cherry trees, which helps explain why the clone idea feels so surprising to first-time visitors.

Where Somei Yoshino came from

The tree gets its name from Somei village, a district of Edo (now Tokyo) that is today part of Komagome in Toshima Ward. From the Edo period into the early Meiji period, gardeners and nurserymen in Somei grew the tree and sold it, at first under the name Yoshinozakura. In 1900 a botanist named Fujino Yorinaga gave it the name Somei Yoshino, combining the village with Mount Yoshino in Nara, the great cherry viewing mountain.

Botanists regard the tree as a hybrid. Its mother is thought to be Edo higan, an early-blooming cherry that grows large, and its father the Oshima cherry, which grows fast and carries white flowers. A genome study published in 2019 supported this parentage. The result is a tree that combines early, abundant bloom with quick growth, which is exactly what the Edo and Meiji gardeners wanted to sell.

Why it has to be copied rather than grown from seed

The key biological reason for cloning is that Somei Yoshino does not breed true. A research paper on the variety describes it as self-incompatible and highly heterozygous, which means that its seeds do not produce reliable copies of the parent. A seed from a Somei Yoshino would grow into a different tree, and it would probably not have the same flowers or the same timing.

Gardeners solved this problem with grafting. A short piece of a parent tree, called a scion, is joined to the lower trunk and roots of another cherry, called the rootstock. The scion grows into a new tree whose blossoms match the parent in size, shape and color, so the offspring is essentially a copy. This is the same method used for many fruit trees and roses, and it is the reason Somei Yoshino can be bought at a nursery as a predictable product.

How one tree became a national symbol

After the Meiji period began in 1868, Somei Yoshino spread widely through parks, schools, riverbanks and other public places. Japan's government information service notes that it grows fast, reaching a size suitable for viewing within about five years of planting, and that its large, showy blossoms suit crowds and picnics. Those qualities made it a favorite for towns that wanted a reliable spring show.

The tree also traveled abroad. In 1912, Tokyo sent 3,020 cherry trees to Washington, D.C., and Somei Yoshino was the largest group, at 1,800 trees. A second gift in 1965 brought another 3,800 Yoshino trees. Today the Yoshino cherries around the Tidal Basin belong to the same clone family that started in an Edo nursery.

Why clones bloom together

Because the trees share their genes, they respond to weather in nearly the same way. A warm spell wakes them at roughly the same moment, and the blossoms then open together over a given region. This synchronization is what makes the spring bloom feel like a single event sweeping the country instead of a scattered set of individual flowerings.

It is also the foundation of the cherry blossom forecast. The forecasts are based on Somei Yoshino at about 1,000 viewing spots around the country, and the calculation weighs temperatures during the dormant and growing periods. Since the trees are genetically alike, the data from one site becomes meaningful at others. Where another cherry is the local standard, such as Hikanzakura in Naha, the bloom arrives much earlier, which shows how much the choice of tree shapes the calendar.

Lifespan, health and the oldest trees

Clones are tied together in their strengths and also in their weaknesses. Somei Yoshino is described as short-lived compared with some other cherries, and a figure of around 60 years is sometimes quoted, though sources treat that as uncertain. The variety is also considered vulnerable to fungal infections, including the disease known as witch's broom, which makes cherry branches grow in odd clusters.

Individual trees can still live far longer when well cared for. A tree in Kaiseizan Park in Koriyama, planted in 1878, has been recognized by a tree health society as the oldest surviving Somei Yoshino, based on radiocarbon dating and other studies. Other early plantings include Hirosaki Castle in 1882. Because of this, many towns care for their old trees carefully, and some also plant other cherry varieties alongside them so that the spring display stays healthy for the next generation.

Not every cherry in Japan is a clone

It is worth keeping the story in proportion, since Japan has far more cherry diversity than the headline suggests. Roughly 100 wild species of cherry grow across the Northern Hemisphere, and about 10 of them are wild in Japan, including Yamazakura. Japan also has more than 100 cultivars bred from those wild species, and old Edo period books recorded over 200 named varieties.

Many famous places show this variety. Hirosaki Park has more than 50 varieties among its roughly 2,600 trees, and Matsumae Park in Hokkaido has more than 250 varieties, which stretches its season well into May. Kawazu in Shizuoka is known for early bloom in February, and Okinawa's Hikanzakura opens in January. Visitors who want to see beyond the familiar white-pink look can seek out double-flowered, weeping and late-blooming types.

What this means when you go to see the blossoms

The clone story adds a pleasant layer to a walk beneath the trees. A row of Somei Yoshino by a river is a kind of living family tree, with each branch ultimately traced to a nursery in old Edo. Researchers have even begun using tiny genetic changes to map how the clones moved around the country, and a recent study of 46 trees from 19 prefectures suggested that four Ueno Park trees may be close to the origin.

For travelers, the practical lesson is simple. Because the clones bloom together, bloom time within one area is predictable, and it pays to check the local forecast and the park's own updates before choosing dates. Visitors who want variety can add a trip to a place with many cherry types. In every case, the flowers last only about a week, and that fleeting beauty is the reason for the whole tradition.

Want to go deeper? Tokyo Paul's book Japan Cherry Blossom Photobook is available on Amazon.

Frequently Asked Questions

Are all cherry trees in Japan clones?

No. Somei Yoshino, the most common variety and the one most forecasts follow, is a clone, but Japan also has wild species and well over 100 cultivars. Places such as Hirosaki and Matsumae grow dozens or hundreds of varieties, each with different timing and flower shapes.

Why can Somei Yoshino not be grown from seed?

It is a hybrid that is self-incompatible and highly heterozygous, so seeds do not grow into reliable copies. Nurseries therefore graft a piece of an existing tree onto rootstock, which produces a new tree with the same blossoms as the parent.

How long do clone cherry trees live?

Many sources describe Somei Yoshino as short-lived, with around 60 years sometimes quoted, though that figure is uncertain. Well cared for trees can last longer, and a tree planted in 1878 in Kaiseizan Park is recognized as the oldest surviving example.

Further Reading

To explore further, see Somei Yoshino (Prunus x yedoensis) and Government of Japan: Cherry Blossoms and Somei Yoshino.

Keep Exploring

More guides from Tokyo Paul: Sakura Varieties: More Than One Kind of Cherry Blossom, The Cherry Blossom Forecast and Weeping Cherry Trees in Japan: Shidarezakura and Where to See Them.