Invasive trees, shrubs, and woody vines pose a serious threat to natural areas in the Great Lakes region, out-competing native plants and damaging wildlife habitat. Invasive woody species can also encroach on farm fields and pastures, prevent the regeneration of trees in timber stands, and restrict outdoor recreation by growing over trails and access points. Additionally, some woody invaders provide ideal conditions for ticks that transmit diseases to people. While every region of North America has invasive species problems, the Great Lakes region’s status as a global transportation hub leaves it vulnerable to a larger number of invaders (U.S. Fish and Wildlife Service).
The Woody Invasives of the Great Lakes (WIGL) Collaborative brings interested partners together to consolidate information on woody invasive plant species. Our goal is to provide residents from all walks of life with the information they need to manage invasive woody plants and restore habitat for native plants and wildlife around the Great Lakes.
December 2021 Update – New Woody Invasive Species Removal Decision Trees
The WIGL Collaborative has developed decision trees to help people, who are perhaps newly discovering that plants that are part of their home landscaping are invasive, prioritize which species should be removed first based on the risk to the surrounding environment, economy, and occasionally, to human health. In a perfect world, everybody would remove all invasive plants from their landscaping right away, but in reality, removing mature woody plants involve a hefty investment of time and/or money. These diagrams can help people with multiple woody invasives in their landscaping prioritize to get the most benefit for their efforts. The decision trees can be found in each woody invasive species profile.
To learn more about the methodology and information used to develop the decision trees and for helpful hints on how to answer the questions, please see the full report here (PDF).
November/December 2021 Update – Newly Regulated Species in Pennsylvania
The Pennsylvania Department of Agriculture recently added Japanese barberry and Callery pear as Class B Noxious Weeds. This means that both sale and cultivation are no longer allowed in the state. However, the Dept. of Ag has announced a phased approach to enforcement, allowing nurseries and vendors two years to liquidate existing stocks. For more information, see Pennsyvlania Dept. of Ag.
August 2021 Update – Landscape Alternatives App & Brochure
The WIGL Collaborative published a brochure highlighting alternatives to woody invasive plants common in gardens and yards in the Great Lakes Basin. An electronic version is now available for free download. We also have print copies of the brochure available for the cost of shipping. Please place your order via The Morton Arboretum Store.
If electronic information is more your speed, we are pleased to announce Version 2 of our popular Landscape Alterantives mobile app. We have added dozens and dozens of new beautiful, versitile, and non-invasive (predominanty native) trees, shrubs and vines. Learn more about the app and how to download it here.
May 2021 Update – New Galleries and WIGL Summit Recordings
We added landscape alternative galleries to the website. Check out these links for a virtual tour of beautiful and non-invasive trees, shrubs, and woody vines & groundcovers. If you’re looking to replace a specific invasive plant, we’ve added mini-galleries to the invasive species profiles as well.
Did you miss the WIGL Summit last fall? If so, you can watch most of the presentations at your leisure. Full playlist here!
We encourage you to use our website to learn more about the woody plants you notice growing in your area and build the knowledge that will help you to be part of the solution! Here are just a few examples of how this website can be used:
Learners & Educators:
- Learn to identify the invasive trees, shrubs, and vines in your neighborhood and the surrounding area and report them in EDDMapS. This website is a resource for woody invasive species in the midwest
Every region of the United States has invasive species problems, but the Great Lakes has larger numbers because it is a transportation hub.
(U.S. Fish and Wildlife Service)
Of the approximately 50,000 non-native species in the U.S. today, less than 10 percent are considered invasive species.
(United States Fish and Wildlife Service)
Several woody invasive species are still popular as landscape plants and are readily available through nurseries and garden centers.
75% of the species evaluated by the WIGL Collaborative produce seeds that are moved over long distances by birds that eat the fruit.
Killing an invasive woody plant is not easy! All of the species evaluated by the WIGL Collaborative frequently sprout from the roots and/or the old stump if only the above-ground portion of the plant is treated (e.g., by one-time cutting, burning, mowing, or grazing).
Some woody plants, such as black locust (Robinia pseudoacacia), are native to North America but become invasive when introduced to new areas far beyond their historic native ranges.
All but two of the species evaluated by the WIGL Collaborative (93%) were purposefully introduced to North America for their horticultural usefulness. Many were introduced by early colonists hundreds of years ago.
The woody invasive species common barberry (Berberis vulgaris) was the target of a massive eradication program in the U.S. lead by the USDA and the departments of agriculture of 17 states because it is a host of the crop disease black stem rust. Between 1918 and 1981, over 400 million common barberry shrubs were destroyed. (United States Department of Agriculture)
Photo Credit: The Great Lakes region is home to many unique ecosystems that are vulnerable to invasive woody plants, including dunes, forests, wetlands, savannahs and prairies (Photo: National Park Service)