Of the 12 species of cherry trees sent to Washington 100 years ago, more than half were Prunus x yedoensis, or Yoshino cherry–a flowering tree whose winter hardiness is matched by its springtime beauty.
The peak bloom, the point at which at least 70 percent of the blossoms are open, isn’t easy to predict. Temperature, frost, and soil moisture play a role, making it hard to give an accurate date more than ten days in advance. Since 1991, National Park Service horticulturist Robert DeFeo has been divining bloom dates by monitoring these five stages of development:
1. Green color in buds. DeFeo usually starts noticing the initial stage of blooming in late February or early March. He says the sunlight-rich south side of the Tidal Basin usually begins this process slightly earlier, “but nobody notices that other than me.”