The Invasive Plants

a girl removes garlic mustard plant from a patch of weeds
A student volunteer removes Garlic Mustard on invasive plant removal day.


Invasive plants are exotic species that tend to crowd out native plants, decreasing their number and variety in an area. They have been brought to North America from other continents for use in agriculture, gardening, erosion control, and medicine—or simply by accident. Invasive plants have the following characteristics: they reproduce rapidly; spread over large areas of the landscape; and have few, if any, natural controls such as herbivores, insects, and diseases to keep them in check. Not all non-native plants are invasive.Many (e.g., chicory, dandelion, curly dock, speedwell, and timothy) have integrated well into local ecosystems and pose no threat to the native plant communities.

Weeding the National Park

Cuyahoga Valley National Park (CVNP) strives to have naturally functioning plant communities in its natural areas. Besides crowding out native plants, invasive plants may change soil and water chemistry and can influence the mix of other plants growing in their vicinity. For example, a number of algae types which naturally occur in wetlands do not occur in wetlands infested with purple loosestrife, and the death rates for American toad tadpoles are also significantly higher in those infested wetlands.

The park and all federal agencies are mandated to control invasive plants when their presence menaces natural conditions. On small, easily controllable populations,hand pulling and removal of the plant is the main method of control. On larger populations, spot treatments of herbicide are used. Large brushy plants are cut down and the stumps are treated with herbicide. Several years of treatment may be needed to kill certain invasive's. Herbicides are not used in areas where they might cause ecological harm. The National Park Service is not trying to eradicate invasive plants—that would not be feasible. Rather, CVNP is focused on removing invasive plants from sensitive areas such as rare plant habitats, wetlands, stream corridors, and other important natural areas.

Invasive Plants of CVNP

Currently, there are 16 plants that are considered to be invasive within the park. These plants invade a broad range of habitats, from pristine forest, meadows, and wetlands, to disturbed roadsides.

Common Name

Scentific Name

Garlic Mustard Allaria periolata
Japanese barberry Berberis thunbergii
Autumn Olive Elaeahnus umbellata
Common Privet Ligustrum Vulgare
Japanese Honeysuckle Lonicera Japonica
Amur Honeysuckle Lonicera Maackil
Morrow Honeysuckle Lonicera Morrowii
Tartarian Honeysuckle Lonicera Tatarica
Purple Loosestrifle Lythrum Salicaia
Reed Canary Grass Phalaris Arundinacea
Common Reed Phragmites Australis
Japanese Knotwood Polygonum Cuspidatum
Glossy Buckthorn Rhamnus Frangula
Eurpean Buckthorn Rhamnus Cathartica
Multiflora Rose Rosa Multiflora
Narrow-leaved Cattail Tyha Angusifolia

Some invasive plants will grow back, but with persistence and repeated control measures, there will be improvement of the habitat over time. In some species like garlic mustard, several years of control will deplete the invasive plant population rather well, while other species are more resistant to treatment and hence require many years and different management methods. Areas managed to date have shown a great ability to recover after removal of invasive plants.

Areas which are severely infested, however, such as those with large populations of Japanese knotweed, are harder to restore by only removing problem species. Planting with native herbs, shrubs, and trees may be required at these sites due to lack of native seed sources, intense competition, or other factors. Controlling invasive species over the long term is complicated. A large part of the solution will be educating landowners, the general public, and garden centers about invasive plants and what they can do to prevent their spread. For more information, visit the National Invasive Species Council website at

Getting Involved

CVNP has developed a volunteer-based, long-term invasive plant monitoring and control program.This program features the adoption of sections of the park by volunteers who are trained to look for and control invasive plants. It is a great chance to experience the lesser known areas of the park while helping to conserve biodiversity. The park also works with community organizations and other groups looking for service projects.

To get involved, visit our volunteer page here.

Last updated: May 30, 2018

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Brecksville, OH 44141


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