An advocacy group concerned about bees says too many retailers are selling garden plants treated with harmful insecticides.
Friends of the Earth has released a study that says half of garden plants the group purchased at 18 different locations in the U.S. and Canada this spring contained neonicotinoids, a class of insecticides that can kill bees.
The plants came from Lowe's, Walmart and The Home Depot, including a Home Depot in Minnesota.
The group hopes the retailers will make changes.
"We think they have a really great opportunity right now to change the whole supply chain by removing neonicotinoids from their shelves and ensuring the plants that they sell don't come pretreated with those insecticides," said Lex Horan, spokesperson for the Pesticide Action Network.
Home Depot officials say their suppliers will be required to label plants treated with neonicotinoids later this year.
A new Minnesota law prohibits retailers from labeling plants as bee-friendly if they are pretreated with harmful insecticides.
MPR News' Elizabeth Dunbar contributed to this report.