The native swamp rose, Rosa palustris, is now blooming at Crow's Nest. Its pink flowers are larger than the more common (and invasive) multiflora rose's white ones, and for us it blooms a bit later. It also lacks the hairy stipules at the base of each leaf stem, or petiole, that you find on multiflora rose. Swamp rose's hips--the fruit--are also much larger. But even if you didn't know this, you could distinguish swamp rose from multiflora rose by its behavior: multiflora takes over everywhere, and swamp rose is a well-behaved clump at the pond, along the stream, and near a spring.
Multiflora rose (Rosa multiflora) is a plant we love to hate. Imported for soil conservation, wildlife habitat, and as a "living fence" to contain livestock, it has taken over many old fields, hedgerows, and wood lots. I lose a lot of blood to its thorns.
A disease called rose-rosette is moving into our area, and it disfigures the new growth on multiflora rose (and some garden roses). The disease reduces the vigor of the plant. Experts think that this will cause multiflora rose populations to be reduced in a cycle of disease boom and bust. It will never eliminate multiflora rose, but perhaps it will never be as dominant as it is today. See links such as this one for more information: http://www.ext.vt.edu/pubs/plantdiseasefs/450-620/450-620.html.