Emeline Rodenas, The Star
AUBURN — A 2012 survey of 120 agencies and landowners in Indiana found $5.7 million was spent to manage invasive species and protect natural areas. The cost grows every year.
A new Terrestrial Plant Rule drafted by the Indiana Department of Natural Resources this month aims to ban future sales of invasive species in Indiana. Until now, Indiana did not have a “do not sell” list of terrestrial plants. The only ban previously existing pertains to aquatic species and went into effect in 2012.
DNR Division of Entomology and Plant Pathology Director Megan Abraham is one of nine people helping with the new rule.
“These are all plants that have been accessed through a tool as invasive. There were various factors take into consideration such as how they reproduce, the type of climate they thrive in and how often they’ve moved off target from a target area,” Abraham said.
The list includes 45 plants, shrubs and trees. All of the plants in question can be found at https://www.entm.purdue.edu/iisc/invasiveplants.php#developed.
If the effort to pass the new rule is successful, the plants will be added to Indiana’s Do Not Sell list, effective 9-12 months from now.
Some of the more commonly known plants on the list include garlic mustard, the common name for Alliaria petiolata; poison hemlock, Conium maculatum; Dame’s rocket, Hesperis matronalis; and purple loosestrife, Lythrum salicaria.
On the national level, agricultural and control costs due to invasive plants are estimated at $15 billion annually, and yet most of these reportedly are still for sale at garden shops.
An invasive species is not just any plant that isn’t native to its region. Rather, it is defined as “a plant that is not native to that region that grows so aggressively that it harms the ecosystem,” said Martha Bishop, owner of Riverview Native Nursery in Spencerville.
Bishop points to native viburnum and invasive honeysuckle as examples. Viburnum berries are about 48.7 percent fat, which helps birds over the cold winter months. Honeysuckle, on the other hand, offers only 0.7 percent fat in its berries.
Invasive plants harm wildlife by crowding out plants that native animals need for food and cover; reducing habitats for beneficial pollinators and predatory insects; and reducing the amount of food available for birds to feed their young. Invasive plants also destroy habitats for rare wildflowers and animals, threatening two-thirds of all endangered species.
Even a few invasive plants can cause quite a headache, DeKalb County Extension educator Elysia Rodgers said. Field bindweed, for example, can stay in a bird’s system for more than 144 hours.
“That can spread quite a long way,” Rodgers said. “One or two doesn’t seem like a huge deal, but it can turn into a problem.”
Until the measure passes and goes into effect, the DNR and the Indiana Native Plant & Wildflower Society will continue to educate the public.
“In the meantime, we educate people as best as we can in the hopes that public demand will turn the tide on these plants,” Abraham added.
Bishop is a co-chair of the INPAWS program committee. The organization plans a quarter of its events to include stewardship, including going on sites to clean up invasives such as garlic mustard and honeysuckle regularly.
“We have a very active stewardship and community partnership with extensions and local preserves. We’re leaving the parks and green areas a better place. We’ve made a commitment to help,” Bishop said. She hopes to see more native plants in garden landscapes.
“My hope is more people would see them to increase awareness of the effects they have. We’d rather have a nursery sell a nonharmful, non-native beneficial plant, even if it’s not native,” she added.
The Indiana Native Plant and Wildflower Society is encouraging the public to contact the state government to help move the measure forward. People can go to in.gov/gov/2752.htm; select the topic Natural Resources, Department of; enter their contact information; add a message that they’d like to see the draft Terrestrial Plant Rule that makes it illegal to sell highly invasive plants in Indiana move forward; and hit submit.
For those who are uncertain about about adding a plant to a landscape in fear that it might be an invasive species, Abraham said, “Call us at 866-663-9684 if you have concerns or suspicions. It’s better to have a false alarm than to find out later that we could have done something, but didn’t.”