The Arnold Arboretum came into existence on March 29, 1872, and is marking 150 years of preserving biodiversity and connecting plants and people. As part of the anniversary celebrations, the Arnold Arboretum welcomes everyone to the first public-observance of its traditional Lilac Sunday event since 2019. In addition, Arnold Arboretum Director William (Ned) Friedman announces a slate of both virtual and in-person talks on sesquicentennial themes entitled The Magic and Meaning of a Garden of Trees. The spring season kicks off on May 1 with the reopening of the Arnold Arboretum Visitor Center in the Hunnewell Building, and accelerates with the approach of Lilac Sunday on May 8. A beloved tradition in Boston for well over a century, Lilac Sunday will return on Mother’s Day, Sunday, May 8, after a two-year pause during the pandemic.