I have a few rose plants and read and post in the rose forum for general information and such I am not partial to ground cover for under roses because ground covers does take nutriants away from the soil that most roses need and tend to have different growing needs I do see your efforts in a more natural mulch type of thing to be honest I would post a message in the rose forum asking for some other secondary plantings I know some folks have somethings in there roses but I don't remember what they call em I'd just be worried of a ground cover with roses is all
not 100% certain but I think some of em use catnip?? it is kind of short upright and blue looked neat too.