Somerville, MA Invasive Plant Rules: Prohibited Species (2026)

Somerville's Native Planting Ordinance, added by Ord. No. 2021-05 on March 25, 2021 and codified at Code of Ordinances Chapter 12, Article IV (Sec. 12-171 through 12-180), sets the city's own planting standards. Sec. " The definition in Sec. 12-174 is broad: an invasive plant is any non-native plant able to establish quickly and spread to the point of disrupting plant communities or ecosystems, and the article expressly folds in any plant on the USDA Introduced, Invasive, and Noxious Plants list for states east of the Mississippi River, plus everything on the Massachusetts Prohibited Plant List published by the Massachusetts Department of Agricultural Resources.

The city may also draw on lists from nonprofit, governmental, or educational sources focused on invasive species in the eastern states. Scope matters here: Sec. " So the ban does not reach a homeowner's existing hedge or a new planting on private land; it governs municipal projects, city parks, streetscapes, bioswales, plazas, and third-party work done on the city's behalf. The same article requires native plants in riparian areas, the Community Path, the Green Line Extension corridor, bioswales, plazas and other city property, at least 75 percent native plantings in city parks each year, and at least 50 percent native street trees each year.

It also phases out neonicotinoid-treated native plants sourced by the city after January 1, 2028 (Sec. 12-178, as amended by Ord. No. 2025-24). By December 31 each year, the director of public space and urban forestry must publish a compliance report on the city's urban forestry website, coordinated with any department that plants or oversees third-party plantings on city land.