Several years ago (May 2013), I was out in Madison WI for a family reunion hosted by my aunt Margo and uncle Don. Margo had some “wild roses” growing in her front flow bed that definitely were NOT Rosa multiflora. She let me dig up and take one of the smaller plants home with me (which was an experience since the rose was quite prickly… I end up buying a large mailing tube at Kinko’s and transporting it in that).
Anyway, it has been hanging on and it finally bloomed this year, which gave me a chance to take a crack at definitively identifying it. I was pretty sure this is a native North American rose. I primarily used Botanica’s Roses (2001) and Helpmefind.com/roses. I thought it might be a Pasture Rose (Rosa caroliniana) but it only has 5-7 leaflets and my rose had 9. The Prairie Rose (Rosa setigera) was another possibility but it describes as having 3-5 leaflets and nearly thornless; Definitely not this rose. There is also Rosa virginiana but according to Helpmefind.com, it grows in zone 5b or warmer. Madison is zone 5a. I guess it is possible that where the rose was growing at my aunt’s hose might have been sufficiently protected to allow R. virginiana to grow but since she was taking no particular care (the rose was a volunteer and might have been classified as a weed), I think it is much more likely that it is an Arkansas Rose (Rosa arkansana). Madison is well within the native habitat and the description fits quite well.