Nashua, NH Landscaping Rules: Native Plants (2026)

Nashua's native-plant policy is incentive-based, not prescriptive. Chapter 190 Article XXVII establishes the City's landscaping standards and requires that all shade trees to be planted as required landscape material shall be hardy for the Nashua botanical zone and have a minimum trunk caliper of 2½ inches measured 6 inches above grade at planting (deciduous), with evergreen trees at least six feet tall, and a mixture of no more than 60% deciduous to no less than 40% evergreen. Inclusion of existing trees in landscape designs is encouraged. There is no Article XXVII mandate that required plantings be NH-native species. The Nashua Conservation Commission and NH DES Soak Up the Rain New Hampshire program publish native-plant guidance especially for riparian and wetland-buffer planting along the Nashua River, Merrimack River, and Pennichuck Brook. NH Agr 3800 (Invasive Species Rule) prohibits planting listed invasives such as Japanese barberry, Norway maple, burning bush, multiflora rose, and oriental bittersweet — pushing landscape designers toward natives by default. Unlike states such as Maryland, Colorado, or Florida, New Hampshire has no statutory HOA xeriscape protection, so HOA covenants may still restrict pollinator gardens, naturalized lawns, or front-yard meadows as a private contract matter. The Nashua city code does not regulate the species composition of private home gardens.