While on a bicycle ride this past weekend, I came upon these large flowering bushes and just had to stop for some photos. I'm not certain, but I believe these are members of the rose family.

The nearest reference I could find was for Rosa multiflora, native to eastern Asia, in China, Japan and Korea. According to Wikipedia, it was introduced to the US "as a soil conservation measure, as a natural hedge to border grazing land, and to attract wildlife."