Hesperis matronalis

dandy line:
Thank you very much for the assistance.
Bruce

AKA Dames Rocket, a non native. Looks nice and flowers copiously. But, it over runs the native populations and eventually kills them off. Considered a noxious weed in Colorado and other states.
I thought they were nice once upon a time and then had to expend a lot of effort in eradication. Be careful what you wish for!

Not known to displace natives in WI. In fact, wherever I see Dame's Rocket, eradicating same would simply leave more room for burdock, buckthorn, etc.

+oM

Dame's Rocket is an invasive species in Wisconsin. As Dandy Line said, be careful what you wish for.

Here is a link that might be useful: Dame's Rocket - Invasive Species

considered by USDA as noxious in these states: Colorado,
Connecticut, Massachusetts; in SW Michigan it does not seem to be a serious problem just as northeastwisc suggested. Although in Connecticut it is classified as: invasive and banned, e.g. illegal to move, sell, purchase, transplant, cultivate, or distribute. I just transplanted some specimens myself because they seem to attract interesting insects and butterflies in the wild; the plants even set seed and I got self-set seedlings at the end of the summer, so they do seem to be quite prolific.

Really!? So all those native Monarda in the photo aren't getting displaced?

Dame's Rocket is invasive in Michigan too, FYI...

http://mnfi.anr.msu.edu/invasive-species/InvasivePlantsFieldGuide.pdf