People in Japan have long loved cherry blossoms and seen beauty in those blooming flowers as well as in the way they flutter to ground. People have felt the sense of the transience of their lives in them. Everything is transient and nothing lasts forever.
But, are the cherry blossoms which people admired and were mentioned about in poems of old and the cherry blossoms which we enjoy viewing now , the same or not? The answer is closer to No.
There was a huge turning point which changed Sakura history drastically. It occurred in 1730 when Somei-Yoshino was created by a gardener in Somei village in Edo, the old name of Tokyo. Before this creation of Somei-Yoshino, the word "Sakura" meant mountain cherry trees which people admired and composed poetry about . Why and when were mountain cherry trees replaced with Somei-Yoshino? Let's compare Somei-Yoshino and mountain cherry trees.
Somei-Yoshino bear more and bigger flowers which are whitish pink. Before the leaves bud, Somei-Yoshino burst into bloom. People enjoy the pure and gorgeous beauty of flowers without leaves. Besides, they increase in number easily, grow rapidly and bear flowers very soon. They are not choosy about soil. But they can be increased by being grafted and the cutting planted. As all Somei-Yoshino have been created from one Somei-Yoshino, it follows that all of them have exactly the same DNA, like clones. They grow sooner but they die faster. They live about sixty to one hundred years.
How about mountain cherry trees. They have been increased by pollinators such as birds or insects. So each tree has a different DNA and shows its colorful characteristics. The flowers have shades of color from white to reddish pink, and the color of the leaves is from red, brown, green to yellow. The leaves grow with flowers. They are less gorgeous than Somei-Yoshino, but they have a classy beauty. Some of them live more than five hundred years, but they take thirty years to mature.
Somei-Yoshino dovetailed perfectly with people's demands that they wanted cherry trees to grow more quickly and bear more flowers sooner.
After the Meiji Restoration in 1867, the army of Japan loved Somei-Yoshino as their characteristics matched the spirit of the army. Eventually Somei-Yoshino became the iconic flower of the army. They planted a huge number of Somei-Yoshino in the army bases throughout Japan. Somei-Yoshino started driving out mountain cherry trees from gardens, parks or Sakura viewing spots.
Nowadays, Somei-Yoshino is synonymous with Sakura and about eighty percent of Sakura trees in Japan are Somei-Yoshino with the same DNA. This means that if conditions like temperature, climate or weather are the same, Somei-Yoshino all over Japan burst into bloom and petals fall at the same time. There are worrying matters. If specific diseases or damage from insect pest occur to Somei-Yoshino, what will happen? Also, after World War Two, so many Somei-Yoshino were planted. Judging from their life span, the time left for them is not so long. One day massive death of Somei-Yoshino can happen. This is not a SF story but a fact.