Trees, Shrubs and Conifers: Shrub ID help, please, 4 by NicoleC

NicoleC wrote:
I found this striking shrub growing on Monte Sano Mountain (7a) in north Alabama; these photos were taken two weeks ago. My local plant gurus have not been able to ID nor have I using botanical keys with regional references. I am about 99% sure it is not a native shrub. There were several planted together, all about 8' tall and 6' wide. It looks like a barberry to me, but I am not sure what kind.

Any help appreciated!