Native Plants for Vermont

Most of New England sits on acidic rock, and most of its native flora is adapted to that. Vermont is a partial exception, and the exception is concentrated in the west.

The Champlain Valley runs on limestone and other calcareous bedrock. Soils there are near neutral or alkaline, considerably richer in calcium, and they support plant communities that do not occur on the granite to the east. Several of the state's rarest species live only on that ground. The clayplain forest of the valley floor, growing on heavy lake-bottom clay, is among the most reduced natural communities in the state.

East and central Vermont is the Green Mountains and their foothills: acidic, rocky, cooler with elevation, northern hardwood forest of sugar maple, beech, and yellow birch giving way to spruce and fir up high.

Which side of that divide you garden on changes the plant list meaningfully, and a soil test that reports pH is the cheapest way to find out where you stand.

Elevation does what latitude does

Vermont is small north to south but tall. Gaining a few hundred feet of elevation shortens the season and drops the effective hardiness zone, so two gardens twenty miles apart can differ by weeks in last frost and by a full zone in winter lows. Cold air also pools in valley bottoms, which means a low, sheltered site can be colder on a clear spring night than the hillside above it.

Plan around the site you actually have rather than the zone the map assigns your town.

Working with clay and with rock

In the Champlain Valley the common problem is heavy clay that stays wet in spring and cracks in August. Deep-rooted species handle it; shallow-rooted dry-site species do not. Plant on the high side of any low spot, and avoid amending individual holes, which in clay makes a basin that holds water.

In the mountains the problem reverses to thin, rocky, acidic ground. That suits the northern hardwood understory flora, the ferns, and the acid-loving shrubs, none of which want fertilizer.

Spring planting is the safer default statewide, with early fall workable in the warmer valley.

Confirming what is native to your county

The Vermont Fish and Wildlife Department's natural heritage program maintains a detailed classification of the state's natural communities, which is unusually useful for matching plants to sites. The Vermont Land Trust and regional conservation districts hold native plant sales, and University of Vermont Extension publishes regional guidance.

Sources: Vermont Fish and Wildlife Department, Natural Heritage Inventory (natural communities and rare species); University of Vermont Extension (regional guidance); USDA PLANTS Database (native status by state).