It’s the season for invasive plant species and the first spring for a new addition to Michigan’s watchlist.
Lesser celandine was added to the state’s invasive species watchlist in July, in recognition of the threat it poses to the ecosystem. The plant, which grows low to the ground and produces yellow buttercup flowers, spreads rapidly, out-competing native wildflowers while starving native insects and contributing to riverbank erosion. It’s one of several invasive species to be on the lookout for and that the state is working to manage, including the spotted lanternfly, itadori knotweed, phragmites, garlic mustard and others.
Due to climate change, Michigan has lost an average of nine days of winter, or days with temperatures below freezing. The warmer winters put Michigan’s cherry, apple, and peach trees at risk of budding too early and allow invasive plants to get a head start. General warming, not just in winter, can increase the prevalence of invasive plants by enabling species to expand their range in previously cooler areas. Globally, climate change and its effect on melting sea ice can open up new channels for invasive species to travel through.
Katie Grzesiak, terrestrial invasive species coordinator for the Michigan Department of Natural Resources (DNR), said this past winter was better than the last few years for managing invasives, including garlic mustard, which is prolific in lower Michigan.
“This winter was a pretty good winter, as far as it actually getting cold,” she said. “And while that doesn’t necessarily kill garlic mustard, in the past couple of years we’ve had some really weak winters, which meant that the garlic mustard had even more time to get started in the spring and grow plentifully and crowd out our native species.”
The 2024-25 winter was the coolest since 2022, but was still warmer than average, according to Climate Central meteorologist and climate specialist Shel Winkley.
“While this winter felt much more ‘wintry’ (especially compared to last year’s record warm winter), it still ended above average by +2.3F,” he said by email. Detroit’s average year-round temperatures have increased by more than 4 degrees Fahrenheit since 1970, according to Climate Central data.
The priority list for tackling invasive plant species is prevention, detection, control and management as well as restoration and rehabilitation, according to the U.S. Forest Service.
Jess MacTavish-Bogda, the invasive species coordinator for the Detroit River – Western Lake Erie Cooperative Invasive Species Management Area, said many people aren’t aware of the issue.
“I think the biggest thing that people can do to help is don’t plant invasive species,” she said by email. “A lot of people don’t know about invasive species or their impacts, so educating people on that is a huge component to our outreach.”
Lesser calendine, for example, was first brought to Michigan to plant in gardens, while garlic mustard was brought to the state and planted for cooking.
“There are certain ones (invasives) that are still allowed for sale or unregulated,” she said, like lesser calendine, in part because the state is gathering information on the scope of the issue. With the new watch listing, people are encouraged to report sightings of the invasive. After gaining more data, the state will have a better idea of how to use funding and resources to address the issue.
Individuals should use boot brushes to remove dirt, possible plant seeds and fragments from shoes, said MacTavish-Bogda. Boaters should also be cautious to pick off vegetation from boats, kayaks, and canoes and wash them with hot water and a cleaner, such as 409 disinfectant.
To actively tackle the spread of invasive species, there are a number of opportunities for people to volunteer to handpick them.
Every week during the summer, Detroit’s Rouge Park hosts a “Honeysuckle Happy Hour” where volunteers pick invasive honeysuckle Friday afternoons and relax afterward with a beverage. The DNR has upcoming invasive plant species workdays at state parks across Michigan including a May 10 meet up at Bald Mountain Recreation Area in Oakland Township to pull garlic mustard.
Reach out to your regional Cooperative Invasive Species Management Area coordinator for local opportunities.
Is there anything a Detroit resident can do when properties adjacent to theirs are full of invasive species & the owner (in my case, absentee landlord) won’t do anything about it & possibly doesn’t know about it? It seems like remediation needs to be at least neighborhood-wide – are there resources? (Personally, I’m battling Japanese knotweed & “tree of heaven” on the edges of my yard. Both properties either side of mine are full of these species and the owners hack them down every now & then, making them worse. Both houses are vacant.)