The annual cherry blossom bloom in Japan heralds the arrival of spring. This year, for the first time in memory, some of those springtime cherry trees have been confused into putting on a show in the fall.
Hundreds of reports of blooming cherry trees have come from all over the country in recent weeks. It primarily seems to be a Yoshino variety, which blossom into the stunning appearance of a white cloud at peak in spring, much like in Washington along the Tidal Basin. Unlike some cherry trees that do occasionally bloom in fall or winter, these types don’t usually do so more than once a year.
Why is this fall bloom happening? The Japan Times offers a cogent explanation:
Hiroyuki Wada, an arborist with the Flower Association of Japan who was interviewed by Weathernews, said cherry blossom buds are created during summer, but they usually don’t bloom until after the leaves fall because abscisic acid — a type of plant hormone that slows plant growth in preparation for the winter — is sent from the leaves to the buds to prevent them from blooming. However, Typhoon Jebi and Typhoon Trami, which landed on Japan in September, carried powerful winds and salty seawater that forced the trees to shed leaves. Warm air also came in from the south, possibly leading the flowers to blossom, he said.
In addition to delivering warm air and stripping many cherry trees of their leaves, cool conditions arrived in the wake of the typhoons. The combination of changeable weather mimicking spring seems to have been the major trigger for a flowery response.
Records of the peak bloom date for Japan’s blossoms have been kept for more than 1,000 years in Kyoto and show a trend toward earlier blooms because of rising temperatures. However, experts do not believe this autumnal oddity will have a major impact on the timing of the bloom next spring or its magnificence.