"Slowly, but persistently, making their way across the land, ecologically invasive plants are the silent invaders of our time," says Elizabeth J. Czarapata in her book Invasive Plants of the Upper Midwest.
Indeed, what looks to most of us like lush, green landscapes are often times a snarl of invasive plant species choking out plants and trees that are indigenous to Wisconsin.
What are invasive species?
The Invasive Plants Association of Wisconsin (IPAW) defines an invasive plant as those that invade native plant communities and impact those native communities by displacing or replacing native vegetation. According to IAPW, Wisconsin has 145 known invasive plant species, including invaders many of us can find in our own backyards such as buckthorn and honeysuckle.
Although the term "invasive species" sounds malicious, many non-native plants gained a foothold in local ecosystems innocently. A good example is garlic mustard, which is native to Europe and parts of Asia. Garlic mustard was most likely introduced to the U.S. as a medicinal herb, says Jan Axelson, natural areas volunteer with the Friends of Cherokee Marsh. However, the plant has long since escaped into the forests of Wisconsin and other states where it forms large, dense patches that out-compete the native wildflowers.
Indeed, you can find garlic mustard in many backyards and city parks. This summer, the Parks department even brought in goats help control the spread of plants like garlic mustard!
“This is the first year for Parks to use [goats as a] management technique and we are hopeful it will help us strengthen our [invasive plant management],” Paul Quinlan, City of Madison Conservation Resource Supervisor, said in a news release. “We hope to continue this practice over the next few years to reduce the abundance of invasives.”
How Can I identify invasive species?
You can find a field guide with pictures of invasive species on Wisconsin's Department of Natural Resources website. Unless you're familiar with the scientific names of plants, make sure to sort the photo gallery by common name. University of Wisconsin also has a handy Weed Identification tool that takes in weed characteristics and generates a likely plant species match.
If you're still scratching your head, you can email the Wisconsin First Detector Network with specific questions about identifying potentially invasive plants at WIFDNcoordinator@gmail.com.
How do I dispose of invasive plants?
For some species, simply cutting down the tree or pulling the plant doesn't guarantee you've purged it from the landscape.
For example, garlic mustard can set seed even after the plant has been pulled, Axelson warns. Even home compost piles don't prevent garlic mustard from germinating because they don't get hot enough to kill the seeds.
Instead, put invasive plants like garlic mustard in your trashcan for disposal at the landfill. (Don't worry, it's legal to landfill any invasive plants on the state's list of regulated species.) For woody vegetation like buckthorn and honeysuckle, pull small plants and cut the larger stems in late summer or fall. To prevent pesky re-sprouting, treat the cut surface of larger stems and stumps with an herbicide or use a non-chemical alternative such as the Buckthorn Baggie to deprive the stump of the sunlight.◼
Megan Handley is a contributing writer and coordinates the publication of The Grapevine.