In summary, this is a plant that grows between hosta in a mostly shady area of my garden. Everyone agrees that it seems to be some type of geranium. The final candidates were geranium thunbergii vs. geranium versicolor. I'd like to make sure, before I spread this around, that this is not a plant that will be invasive or otherwise cause problems in Minnesota. (I have an unfortunate history of being partial to goutweed and chameleon plant)
Does anyone know a reason for me to steer clear of this plant?
StPaulPeg, I don't know anything about these plants. When I'm in doubt about a plant's invasiveness, I just type the species name and 'invasive' into the search bar and see what comes up. Sometimes it's just gardeners grousing about a plant that spread two feet into the wrong spot, sometimes you'll read about much more serious problems, like plants choking a waterway.
I do know there are some native geraniums that are similar, like Geranium maculatum. Those might interest you. I hope to have some seeds next year. . .. :)
When in a position to do so, you should share a photo of the plant you are deliberating over. Something isn't quite right to me with that having been identified as Geranium versicolor. Close up photos would help even though you won't be able to share any for a long time.