Invasive species are flora and fauna that live outside their historic, native ranges. Outside their native habitats, limitations on these nonindigenous species are reduced or disappear entirely, giving them a huge advantage over native species.

A partial list of invasive plant species with a significant presence in Denison’s Bio Reserve

Amur Honeysuckle
(Lonicera maackii)

Photo of Amur Honeysuckle

Common invasive shrub, along with Morrow’s honeysuckle (Lonicera morrowii) and Tatarian honeysuckle (Lonicera tatarica), that forms dense thickets, shading out native plants and reducing biodiversity.

Garlic Mustard
(Alliaria petiolata)

Close up photo of the garlic mustard flower.

This herbaceous plant is a major problem, forming dense mats that inhibit the growth of native wildflowers and tree seedlings.

Multiflora Rose
(Rosa multiflora)

Photo of a Multiflora Rose plant.

This thorny shrub forms dense thickets, outcompeting native vegetation and creating barriers for wildlife.

Autumn Olive
(Elaeagnus umbellata)

Photo of the Autumn Olive plant.

This shrub was introduced for landscaping and erosion control but has become invasive, spreading rapidly and outcompeting native plants.

Russian Olive
(Elaeagnus angustifolia)

Photo of a large Russian Olive shrub.

Similar to Autumn Olive, Russian Olive was introduced for landscaping and erosion control but has become invasive, spreading rapidly and outcompeting native plants.

Oriental Bittersweet
(Celastrus orbiculatus)

Photo of the leaves of the Oriental bittersweet plant.

Oriental bittersweet has the ability to aggressively climb and smother native vegetation, including trees and shrubs, making it a major concern for forest health and biodiversity.

Tree of Heaven
(Ailanthus altissima)

Photo of the leaves of the Tree of Heaven plant.

The tree of heaven is a rapidly growing deciduous tree native to China that has become a widespread invasive species across North America.

Japanese Stiltgrass
(Microstegium vimineum)

Photo of Japanese stillgrass.

This annual grass forms dense mats, shading out native plants and reducing the availability of food and habitat for wildlife.

Callery Pear
(Pyrus calleryana)

Photo of a Callie Pear tree in bloom.

While often planted as ornamentals, these trees are now spreading rapidly, outcompeting native trees and creating monocultures.

Winter Creeper
(Euonymus fortunei)

Photos of leaves of a Winter Creeper plant.

This vine can climb trees and shrubs, eventually causing limbs to break and potentially killing the host plant.

Privet
(Ligustrum sinense)

Photo of the leaves and berries of a Privet plant.

Privet can dominate the shrub layer and often becomes the only shrub underneath trees, especially in streamside areas.