Lilacs have been used for over a century in Europe to study the timing of plant development and how it is affected by weather. For almost 40 years, cooperators in the United States and Canada have assisted phenological researchers by reporting event dates for lilacs, including one of the original studies of phenology in the western United States (Caprio 1966). Lilacs were selected because of their well-defined phenological events, cold hardiness, and resistance to heat and drought.

The bloom time of lilacs can be used to predict the best time for certain farming activies. In Montana, alfalfa is usually ready for its first cut one month after lilacs start to flower. Also, when the lilacs reach full bloom is the best time to treat gypsy moth larvae on deciduous trees.