I'm thinking something from the Fabaceae family (beans and legumes), but I couldn't say what.

Thank you. Not a vine or a climber tho, ie not PI!

I'm not 100 percent confident but possibly Baptisia alba var microphylla? It has the zig zag stems. My 1st thought was Ptelea trifoliata, which is uncommon or absent in your county.

Jay's suggestion is a good one, but a pic of Baptisia doesn't seem to have the little leaves at the leaf-stem axils.

Desmodium ??

It's three leaves, but NOT like the poison stuff. In the poison stuff, the center leaf extends beyond the other two with a small length of stem that the other two leaves don't have.

I have t assume it is some kind of Baptesia, maybe Big Leaf, but not sure how it got here. I do have white Baptesia fairly close by too, but the leaves are much smaller.

Will have to wait until next year to see if it blooms.

I looked at Desmodium, Lespedeza, all Fabaceae in Minnesota and several Baptisia photos. There aren't any Baptisia species that have smaller leaves ggrowing along their stems, so I think the smaller leaves are because of the conditions it's growing in. Were the stems cut back? This pic of Baptisia alba macroophylla shows smaller leaves, but the leaves of the pictured plant seem to be differently shaped than your plant, which could be because of it's conditions also, or the leaf shapes are variable in this species? The zig zag stems are a perfect match.

Baptisia alba var macrophylla

Ok, I found it growing elsewhere on my property. Here it is: drum roll--------------

Thermopsis !

Either carolinium or montanum. Not sure which.

I started some thermopsis from seed about ten years ago and they have populated different areas now. In fact I was working in a different area yesterday and saw the little shamrocks in the axils and was immediately aware.

This is a young plant, the stem about 3' tall. I have mature plants that are 6' in length.

Maybe that's why your Thermopsis looks so familiar because I see my Thermopsis villosa/caroliniana every day. It's not even close to being native in Minnesota, and you are the only person growing it, in Minnesota afaik? It's common for these native Fabaceae to produce skinny, flimsy stems that flop over. I thought I was growing it at it's northern limits, but it's hardier than I thought. I bend the zone rules and like others that do it also. Can you grow Fire Pinks, Silene virginica up there?

Jay-I think I bought seeds of T montana and they are perfectly hardy here in Z3, and I'm getting some spreading, some encroached on my white Baptesia this past year. They do not flop either.