Theory and beauty are wonderful, but the Carex ended up where
1. there was space
2. there was irrigation
When the transplanted roses re-foliate, and the Carex grows a little, they will be fine.
Although they would have been a lovely contrast to blue Agaves, there was insufficient water near the Agaves to to keep Carex alive. They are not in a group together, either, but in the same area, and close enough together to qualify for the "repetition" factor in good design. They complement Geranium 'Rozanne', annual blue-flowered Lobelia, the dark-foliage Dahlias, and as it happened, look quite good with the apricot roses--with both the flowers and the bronze new foliage.
Though I couldn't partner them with blue Agaves, still I am glad to have gone to all the trouble of photographing them with many different plants. Hopefully I learned something from all that. I did put the puppies in the kennel while I planted the Carex, so at least they didn't eat any wire or rubber gasket or anything else while I wasn't there to watch over them. So I guess I learned something. Keep puppies and gasket separate!
Boris sulks for gasket chewing.