There’s the calendar, and then there’s reality. So while the first day of Spring is officially set for March 20, many areas of the U.S. are reporting plants and trees budding out or blooming much earlier than average (shown in red on the map above). In fact, parts of the Southeast, lower Midwest, mid-Atlantic, and New York City area are seeing either the earliest spring on record or a spring that only occurs once every 40 years, according to the National Phenology Network (NPN). For lawn and landscape pros, it means work may start earlier. it can also mean accelerating pest control timelines.
Spring leaf out continues to spread north, arriving several days to weeks earlier than average in much of the Southeast, lower Midwest, and mid-Atlantic, reports NPN. Indianapolis, IN is 22 days early and Philadelphia, PA is 20 days early. Spring bloom has also arrived days to weeks early in the Southeast. It’s 22 days early in Charlotte, NC.
The peak bloom for Washington D.C’s famous cherry blossoms at the National Mall and Memorial Parks is expected nine days earlier than average, reported The National Park Service this week. It’s now projected as sometime between March 22-25. The peak bloom date is defined as the day when 70% of the Yoshino Cherry (Prunus x yedoensis) blossoms are open. Extraordinary warm or cool temperatures have resulted in peak bloom as early as March 15 (1990) and as late as April 18 (1958). For more on the Bloom Watch, click here.
According to an article by CNN meteorologist Jennifer Gray, “Much of the ‘early spring; has to do with the warm start to 2023. Much of the South and Southeast are off to their top-10 warmest years on record, and several cities are seeing their top-five warmest: Houston, Jackson, Nashville and Atlanta. It is even more dramatic in the mid-Atlantic and Northeast. Philadelphia and New York City are experiencing their warmest start to the year on record.”
Other areas of the U.S. though, are seeing a later Spring, according to NPN. The West is a mix of early and late. Parts of Arizona are seeing a spring that only occurs this late once every 40 years. Southwest UT is days to over a week late and Portland, OR is 2 days late. Spring bloom is days to over a week late in the Southwest. It’s 6 days late in San Francisco, CA.
Interestingly, 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.
Will it affect pest control timing?
Of course, an early Spring can also mean lawn and landscape professionals may want to accelerate their pest control timelines. According to NPN Director Theresa Crimmins, “…it is true that many insects do emerge from diapause earlier in the year when temperatures are above average. In addition, mild winters can allow more insects to overwinter, and longer growing seasons allow many species to undergo additional life cycles, resulting in larger populations.”
To gauge whether early Spring temperatures are affecting pest insect populations and improve efficacy, NPN also offers Pheno Forecast maps which predict key life cycle stages for 12 species of insects and one invasive plant species. Pheno Forecast maps depict, on a given day, the status of a species’ life-cycle stage across the contiguous U.S. Maps include: Apple maggot, Asian longhorned beetle, Bagworm, Bronze birch borer, Buffelgrass, Eastern tent caterpillar, Emerald ash borer, Hemlock woolly adelgid, Lilac borer, Magnolia scale, Pine needle scale, Red brome, Spongy moth, Winter moth, and Winter wheat. Simply click on these links for the current map. For instance, shown below is the hemlock woolly adelgid six day forecast from March 6.
Do you have a suggestion of another species for which a forecast would help you make decisions? To provide your feedback on Pheno Forecast maps, ciick here.