Where leaves are emerging and flowers are blooming
It’s that time of year again when we hear about how the plants are growing across the country. For the Washington Post, Ben Noll, John Muyskens, and Naema Ahmed have the maps for leaves and flowers.
Meteorological spring started March 1. The astronomical season started March 20. But there’s a third option: The season as decreed by the plants. They don’t follow any calendar and instead leaf out when it’s warm enough.
The first emergence of leaves can be estimated by temperatures since the start of the year. A certain amount of warmth needs to accumulate before leaves appear. This warmth is typically measured through a metric called growing degree days.
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