I have a patio rose in a large pot and in the summer I've planted lobelia and surfinias or petunias (you could plant your choice of annual bedding plants, choosing nice colour mixes) and in the winter I've planted violas. The violas flowered a bit late autumn but really came out in the spring. I think you could probably plant whatever you would if it was in a bed in the garden if you prefer perennials. I feed with fertiliser to keep it all going and water regularly in the summer, though this summer England's been pretty wet!
