Last Thursday, I noticed a crew of three workers walking around the pond spraying. I chatted with one who said they were from Prairie Restorations, under contract with the City of Northfield.
They were killing Bird’s foot trefoil, described on their website as an exotic species of wildflower.
In some cases exotic species find just the right niche and become highly competitive with native species already in place, reducing diversity and upsetting stable communities of both plants and animals.
See the Wikipedia for more about Bird’s-foot Trefoil. And see the Prairie Restorations blog for lots more about their recent activities in restoring prairies around Minnesota.