What is this plant?
This may be a native perennial geranium: http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c870 Flowers are purple-pink. This is sold as a groundcover.
There is also a "weed" geranium, which is also native, which is appropriate for natural areas. It has white to light pink flowers. Leaves vary, but don't look too much like yours.
At any rate, you might want to let it bloom so you can id it, and then decide what you want to do. If it is too happy and aggressive where it is, you may be able to use it elsewhere as a groundcover--win-win.