Invasive Species at Minute Man NHP

Minute Man National Historical Park acts as a refuge for native North American plants, but it also hosts a variety of non-native and invasive plants. To preserve the natural and historical integrity of the park, biologists and volunteers at Minute Man NHP take measures to control invasive plants where it is possible.
Thousands of purple flowers crowd the riverbank beside the Concord River.
Though beautiful, purple loosestrife crowds native plant species and reduces species diversity.

NPS photo

Invasive plants typically have origins in places other than where they infest. In many cases, invasive and non-native plants present in New England are native to the Eurasian continent. The plants are introduced to new areas when they are brought intentionally for ornamentation or agriculture, or accidentally as seed “hitchhikers”. Areas with disturbed natural vegetation are more readily populated by these invasive newcomers. Because New England has been extensively farmed for hundreds of years, it is a prime spot to become host to invasive species.

In the summer, one of the most prolific invasive plants present in the park is purple loosestrife, which covers wetlands within the park in a purple haze. While visually appealing, this plant is considered invasive because it aggressively spreads, and competes with native species. Through competition for sunlight and soil, it diminishes the number of native plants within an area, like native cattails. By choking out competition, the invasive can multiply and take over a landscape.

Two other invasive plants found within the park are black swallowwort and garlic mustard. Each of these plants has a native counterpart but can be deadly to the insect larvae that hatch and eat the leaves. In fact, many native animals cannot eat introduced plants. Without this natural source of control, the invasive can spread. A landscape dominated by an invasive plant has a lower capacity to support native flora and fauna—from other plants, to large mammals. The landscape is altered on a large scale.

Small white garlic mustard flowers with green leaves.
Garlic mustard is an invasive species found within the boundaries of Minute Man NHP.

NPS photo

To control the invasive plant population within park boundaries, park officials and volunteers use a variety of methods. One method is chemical control, where carefully selected chemicals are applied to the invasive plants to kill the plant. Other control methods do not rely on chemicals, such as the mechanical removal of the plant with machinery, and the manual removal of the plant or its seeds by hand.


Wild Chervil

Black Swallowwort

Spotted Knapweed


Japanese Barberry

Garlic Mustard

Japanese Honeysuckle

Asian Bush Honeysuckle

Morrow’s Honeysuckle

Oriental Bittersweet

Winged Burning-bush


Leafy spurge

Black Locust

Purple Loosestrife

Greater Celandine

Japanese knotweed

Creeping Buttercup

Glossy and Common Buckthorn

Multiflora Rose

Norway Maple

Sycamore Maple

White Turtlehead



Yellow Flag Iris

Japanese stilt-grass


Minute Man National Historical Park

Last updated: November 2, 2020