Native Plants for New Hampshire

New Hampshire covers an extraordinary span for its size. The short seacoast and the lower Merrimack Valley in the southeast have the longest, mildest season. Move north and west and the land rises through hills into the White Mountains, where the Presidential Range carries the largest area of alpine habitat in the eastern United States south of Canada.

That alpine zone is a genuine arctic remnant, holding species that otherwise grow hundreds of miles north. It is fragile, protected, and not a source of garden plants, but it explains the state's reputation for severe conditions: the summit weather is among the harshest recorded anywhere.

For gardeners the practical range is from the southeast, where a reasonably long season allows a broad plant list, to the northern counties, where the season is short and only genuinely hardy species are worth planting.

Granite means acid, and acid means a specific plant list

The state's nickname is accurate about the bedrock, and the soils formed from it are acidic, often thin, and frequently stony. Rather than a limitation, this is a clear instruction about what to plant.

Acid-loving natives thrive without any intervention: lowbush blueberry, sheep laurel, rhodora, wintergreen, and the ferns and sedges of the northern hardwood understory. Mountain laurel reaches its northern limit in the southern part of the state and is spectacular where it is hardy.

The exception worth knowing is that pockets of richer, less acidic soil occur in some valleys, and they support a noticeably different and more diverse flora. A pH test tells you which situation you are in.

Sites, slopes, and cold air

Slope and aspect do a lot of work here. A south-facing slope warms early and drains well, suiting dry-site species. A north-facing slope stays cool and moist and holds a woodland flora. Valley bottoms collect cold air and frost earlier than the hillsides above them.

Plant in spring through most of the state, or early fall in the southeast. Snow cover insulates where it is dependable. Leave stems standing over winter and cut back in late spring, after overwintering insects have emerged.

Confirming what is native to your county

The New Hampshire Natural Heritage Bureau documents natural communities and rare plants statewide, and the New England Wild Flower Society tradition, now continuing as Native Plant Trust, maintains regional guidance and a plant conservation program covering all six New England states.

Sources: New Hampshire Natural Heritage Bureau, Department of Natural and Cultural Resources (natural communities); Native Plant Trust (New England flora and conservation status); USDA PLANTS Database (native status by state).