The following is a report from the Midwest Invasive Plant Network Listserv of a new invasive species in the Midwest
One of our park partners along the Mississippi river near St. Paul
identified an explosion of Cardamine impatiens (narrow leaf bittercress)
in a restoration area we have been working on. The explosion was akin
to something that we might see with garlic mustard. Lots of seedlings
in dense patches in the early season under shaded canopy. We also found
another 10 ft by 10 ft patch of it in Minnetonka.
Attached is a link to a MI fact sheet which does list it as invasive but
with a very limited distribution. The sheet also provides pictures and
keys to its identification. Please keep an eye out for it and remove
any you may see.