Lilacs: Spring's Favorite Perfume
In sync with the Midwest
Lilacs are perfectly in sync with our Midwest winters. Most varieties need a cold dormancy period of at least 850 hours (about 35 days) at temperatures below 45 degrees to flower. Each species and variety has its own bloom season (classified as early, mid and late). If you plant the right types, you could have lilacs in bloom for several weeks, ending with the Japanese tree lilac.