Invasive Plants

Purple loosestrife flowers
Purple loosestrife's bright magenta flowers seen along Marshall Brook in Acadia National Park.

NPS/FOA photo by Will Greene

Nearly a third of the park’s plant species are non-native, and some of these species are extremely invasive and threaten the integrity of our natural communities. You will find invasive plants spreading into the more pristine and less disturbed areas of Acadia’s forests, wetlands, and islands.

Purple loosestrife (Lythrum salicaria) is one species that has been actively managed in park wetlands since 1988 and after 30 years of intensive management, purple loosestrife populations at Acadia National Park are at very low levels.

Acadia’s Invasive Plant Management Team (IPMT) monitors the park’s forests and wetlands for the presence of 25 invasive plant species every year and removes what they can. Other than purple loosestrife, some of the most problematic species at Acadia include shrubs like glossy buckthorn (Rhamnus frangula), Japanese barberry, (Berberis thunbergii), and Morrow’s honeysuckle (Lonicera morrowii); vines like Asiatic bittersweet (Celastrus orbiculatus); and herbaceous plants like Japanese knotweed (Fallopia japonica). See below for a full list of Acadia's target invasvie plant species.

Glossy buckthorn (Frangula alnus)

Amur maple (Acer ginnala)

Asiatic bittersweet (Celastrus orbiculatus)

Autumn olive (Elaeagnus umbellata)

Barberry (Japanese & Common) (Berberis thunbergii, B. vulgaris)

Bull thistle (Cirsium vulgare)

Burning bush (Euonymus spp.)

Bush honeysuckle species (Lonicera spp.)

Canada thistle (Cirsium arvense)

European bittercress (Cardamine impatiens)

Foxglove (Digitalis purpurea)

Garlic mustard (Alliaria petiolata)

Giant hogweed (Heracleum mantegazzianum)

Japanese honeysuckle (Lonicera japonica)

Japanese knotweed (Fallopia japonica)

Lupine (Lupinus polyphyllus)

Multiflora rose (Rosa multiflora)

Norway maple (Acer platanoides)

Privet (Ligustrum spp.)

Purple loosestrife (Lythrum salicaria)

Spotted knapweed (Centaurea stoebe)

Yellow iris (Iris pseudacorus)

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Acadia's Invasive Plant Management crew cuts down a fruiting glossy buckthorn shrub with a handsaw in an alder wetland at the foot of Champlain Mountain.

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    Last updated: August 4, 2021

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