Thousands of plants have been introduced to the United States from other parts of the world, either intentionally for horticultural use or accidentally, transported along with other products. Once here, separated from the natural predators or conditions that kept them in check, they become invasive and can threaten native species. The U.S. Fish and Wildlife Service estimates that invasive species, including plants and animals, cause more than $120 billion in damages each year.
Holden Forests & Gardens works to control a number of invasive plant species on its properties, eliminating species from our collections that have been determined to be invasive and replacing them with non-invasive landscape plants.
In the gardens and collections, the staff has removed examples of privet hedges, burning bush (Euonymus alatus) and Callery pears (Pyrus calleryana). Doublefile viburnum (Viburnum plicatum) that produce fruit were also removed. While not officially listed as an invasive, the staff observed large vigorous seedlings in quantity in the natural areas, such as Stebbins Gulch, and opted to be proactive. Snowball types of this species were left in place, as they are essentially fruitless and not considered invasive.
In the extensive natural areas at the Holden Arboretum, members of the conservation staff regularly remove species such as burning bush, invasive species of honeysuckle and garlic mustard from the grounds.
As part of our mission, we also seek to inform the public about the negative economic, environmental and human health impacts these plants can cause through a combination of onsite displays, publications and programs.
In addition to the work being done at the Holden Arboretum an Cleveland Botanical Garden, Holden Forests & Gardens also supports the efforts of the Ohio Invasive Plant Council. The organization has created a scoring system, based on similar systems used in other states, to evaluate if a plant species is invasive in Ohio.
There are a number of plants on the list that are not sold commercially and not generally planted but are rapidly spreading throughout Ohio and severely degrading native plant communities, resulting in a loss of native biodiversity. Hopefully, this raises awareness of homeowners and land managers that they should try to control invasive species on their property.
However, there are notable additions to this list that include common commercially available plants, including Japanese Barberry (Berberis thunbergii) and all cultivars of Callery Pear (Pyrus calleryana). These should no longer be sold or grown in Ohio, so nurseries, garden centers, and landscapers need to eliminate them from their planting lists and replace them with something non-invasive in their landscapes.
For a complete list of the plants deemed invasive in Ohio, visit the Ohio Invasive Plants Council website to see the results of their assessment.