This message for the start of spring comes from the masterpiece Treasury of the True Dharma Eye (Shobo Genzo) by Dogen, the founder of Soto Zen.
The passage is taken from Fascicle 44, Flowers in the Sky, written in 1243:
Thus, when the time comes, flowers open. This is the moment of flowers, the arrival of flowers. At this very moment of flowers arriving, there is no other way. Plum and willow flowers unfailingly bloom on plum and willow trees. You see the flowers and know plum and willow trees. You understand flowers by looking at plum and willow trees. Peach and apricot flowers have never bloomed on plum and willow trees. Plum and willow flowers bloom on plum and willow trees. Peach and apricot flowers bloom on peach and apricot trees. Flowers in the sky bloom in the sky in just this way. They do not bloom on other grasses or trees.
Seeing the colors of flowers in the sky, you fathom the limitlessness of fruit in the sky. Seeing the opening and falling of flowers in the sky, study the spring and autumn of flowers in the sky. The spring of flowers in the sky and the spring of other flowers should be the same. Just as there are a variety of flowers in the sky, there should be a variety of springtimes. This being so, there are springs and autumns in the past and present.
Those who assume that flowers in the sky are not real and other flowers are real have not seen or heard the Buddha’s teaching. To hear the words that the sky originally had no flowers and assume that the flowers in the sky that did not exist do exist now is a lesser view based on shallow thinking. Step forward and think deeply.