My first impression is that it's one of the Oenothera/Evening primroses.

Thanks for the comments. I tried to get a closeup of the flower but it came out fuzzy. There are five petals however.

The Minnesota Wlidflowers site lists ten different species of Lysimachia.

My impression was that the leaves are narrow, not broad. The plant is still quite small but maybe just a juvenile at this point.

It is definitely an attractive plant so I will endeavor to keep it going. There has just been a 2" rain over night so cannot get any new pics for a while.

Looks like Common Evening Primrose (Oenothera biennis) to me.

☛ Common Evening Primrose info. ☚

I really don't think it is Oenothera biennis. For starters look at the scale of the fingers in the final picture. The flowers are thumbnail size. I'm still going with Lysimachia.

The size of plants and flowers for O. Beinnis are quite variable depending on light and moisture levels -- I've seen ones with flowers the size of a US dime.... The flowers just don't match Lysimachia to me. They have the more open form of Primroses , IMO. The poster will have the final word, I guess since they see the plant & flowers most clearly in person ;)

My first impression was Lysimachia. If you look at the 2nd pic above, you can see the petals have a point on the margin like Lysimachia instead on an indentation like Oenothera.

I would go with Lysimachia.

No expert here, but I'm inclined to agree with floral_uk that it is fringed loosestrife (Lysimachia ciliata). I recently asked about it myself.

I went out between raindrops(4.5 inches of rain in 48 hours-woohoo), and got some more pics. Hope these show up before Flo's bedtime so she can view.

100% Lysimachia.

But you're right, I should be going to bed.... not clicking around on the web. Good Night.

Oops, I think I'm going to stir up the pot again. Looking on the Mn wildflowers site, the Lysimachia hybrida (Lowland Yellow Loosestrife) looks like a better candidate. What has bothered me about the L ciliata was that it has broad leaves while my specimen is showing narrow leaves. This is a link to the Yellow Loosestrife entry.

https://www.minnesotawildflowers.info/flower/lowland-yellow-loosestrife

Is there an easy way to distinguish between the two?

Not pot stirring at all - I haven't ever stated categorically that it is L ciliata. Only that it is a Lysimachia. My wording was 'compare with L ciliata.' ie that would be a good place to start looking. I do not have wide knowledge of N American native flora although I can sometimes suggest a genus or even a comparable species as a starting point.

Here is a snip of the part of Alan Weakley's Lysimachia key that applies to your plants. It was captured as a photo, so click on it to see it in larger form. I can't see enough detail in your photos to determine species, but you should be able to work through the options.