The grasses are head-high and higher now, after weeks of rain, along the paved marsh trail; the air filled with birds of an early morning and in the evening --- ranging from big red-wings to tiny warblers --- and those mosquitoes, a huge issue in the back yard, not so much down here. So take a walk.
I'll follow a pretty flower anywhere and some of the prettiest right now aren't native --- in fact some are border-line invasive if not outright so.
Crown Vetch (Securigera varia) came to us from Africa, Asia and/or Europe --- and has been widely loved by highway builders who have planted masses of it to control erosion. It loves the Midwest especially, and will grow where it's planted, forming dense mats with the potential to crowd out natives. Say it lands in a prairie fostered by regular burns --- well, burning encourages crown vetch, too. Enlarge the photo below and you'll see a tiny spider.
Bird's-foot-trefoil (Lotus corniculatus) came to us from Eurasia and/or North Africa and was introduced as forage --- seemed like a good idea at the time. Now it flourishes and is looked upon by many as an invasive.
Red Clover (Trifolium pratense), although native to Europe, western Asia and northwest Africa, is not really an issue --- it's a short-lived perennial, planted as fodder and as a popular "green manure." But it is a guest.
The native plants abloom now at the marsh are white. I found Prairie Dogbane (Apocynum cannabinum) in abundance along the trail (look for the red stems).
And a whole field of Foxglove Beard Tongue (Penstemon digitalis), moving just beyond their blooming prime right now. Like dogbane, it's a native. Look carefully, and you'll see that the flowers are hairy.