identity of shrub
This is not native, and is, in fact, invasive and you should remove it.
It is Autumn Olive (Elaeagnus umbellata) which was widely planted as an ornamental, wildlife habitat and forest restoration in the 1800's, but has now become a threat to native ecosystems by out-competing our native plants. You see it along many of our highways, notable for the silver leaf undersides.
A video about it from our office can be found here: http://extension.umd.edu/hgic/problems/invasive-plants-video-playlist