The Lilac bush at the beginning of our walkway is in full bloom. The purple flowers waft a fragrance that instantly tells me summer is on our doorstep. I was once told that years ago a Lilac in front of a New England house also told traveling salesmen that they were welcome to stop at the house and pitch their wares. But the history of the much-loved lilac remains largely mysterious.
Lilacs have been a New England tradition for hundreds of years. Syringa vulgaris is the state flower of New Hampshire and according to the state statute, “is symbolic of that hardy character of the men and women of the Granite State.” The oldest living lilacs in North America may be those at the Governor Wentworth estate in Portsmouth, New Hampshire, perhaps planted around 1750.
The Lilac genus, a member of the Olive family with 20 to 25 species and hundreds of varieties, are native to Eastern Europe and Asia. They made their way to England sometime before 1630, when they first appeared in writing there. Their history in the New World is intertwined with some of our most famous historical leaders. In 1767 Thomas Jefferson wrote about his method for planting lilacs in his garden book. On March 3rd in 1785 George Washington wrote that he “took up the clump of Lilacs that stood at the corner . . . and transplanted them to the clusters in the Shrubberies and standards at the South Garden gate.” On April he noted that leaves of the lilac “had been out many days, and were the first to show themselves.”
Phenology is the study of the seasonal occurrence of developmental or life cycle events, such as bud break, flowering, or autumn leaf drop. The timing of these events is known to be sensitive to short- and long- term variability in climate and is thus a robust indicator of the effects of climate change, especially observed rising temperatures.
Botanists and gardeners have been carefully tracking flowering phenology of lilacs in New England for decades. A recent analysis of the data stretching from 1965 to 2001 indicated that flowering now occurs four days earlier. And modeling suggested that this trend will continue.
According to the Northeast Climate Impact Assessment (see full report at http://www.northeastclimateimpacts.org) first-leaf and first-bloom dates are projected to arrive more than two days earlier per decade under a high-emissions scenario —arriving almost three weeks earlier by the end of the century. Under a lower-emissions scenario these dates would arrive roughly one day earlier per decade (or one to two weeks earlier by the end of the century).