WHAT IS THE DIFFERENCE BETWEEN FIRST LEAF AND FIRST BLOOM?
The First Leaf Index is based on the leaf out of lilacs and honeysuckles, which are among the first plants to show their leaves in the spring. This Index is associated with the first leafing of early-spring shrubs and other plants.
The First Bloom Index is based on the flowering of lilacs and honeysuckles. This Index is associated with blooming of early-spring shrubs and leaf out of deciduous trees.
HOW DOES THIS SPRING COMPARE TO “NORMAL”?
Spring leaf out continues to spread up the country, three to four weeks earlier than a long-term average (1981-2010) in some locations. Boston, MA and Providence, RI are 2-3 weeks early, Indianapolis, IN is 4 days early, Pueblo, CO is 1 week late, and Reno, NV is 1-2 weeks early.
Spring leaf out has also arrived in parts of the West. It is on time to 2 days late in San Diego, LA, and San Francisco, CA and 10 days early in Portland, OR and Seattle, WA. Parts of the Columbia Plateau are 30 days early.
Spring bloom has also arrived in several Southeast and Southwest states. Spring bloom is between 1 day and 3 weeks early.
HOW OFTEN DO WE SEE A SPRING THIS EARLY OR LATE?
Darker colors represent springs that are unusually early or late in the long-term record. Gray indicates an average spring.
In parts of the Southeast and Northwest, this year’s spring is the earliest in the 39-year record (dark green).
Source: USA National Phenology Network, www.usanpn.org