Took a little walk down to the water. Siena Retreat Center. That pretty purple flower is crown vetch, unfortunately invasive in our region.
“Crown Vetch was introduced into the United States from Europe by various transportation departments for erosion control and highway beautification. It is still planted as an ornamental plant in flower gardens, even though it invades natural areas readily.”
https://www.illinoiswildflowers.info/…/crown_vetch.htm
Thanks for this post. Several participants commented how pretty this flower was. I too, tried to explain the complicated story of invasives.