On March 25, 2021, the Somerville, MA City Council unanimously passed a first-of-its-kind ordinance requiring that plantings on city-owned land be composed primarily of local native plants.

Local advocacy group Green & Open Somerville has been collaborating with Katjana Ballantyne and other city councilors for several years to author the ordinance. It requires 100% native plants along rivers, the Somerville Community Path, and Metro Train Extension, 75% native species in parks, and 50% native trees along streets. Native plants are defined in part as “ a plant that is a part of the balance of nature that has developed over hundreds or thousands of years in a particular region or ecosystem.”