Cinta, thank you. Yes they do get better with age. I can't remember if I have cut my yellow ones back or not, but they are much fuller now than they were at first. Literally they produce blooms all summer, clear into October. To me, they look like yellow butterflies dancing. i have yellow and purple echinaceas in that same bed, nepetas, salvia, coreopsis, helianthus, rudbeckia, and baptisia-both yellow and purple, and 8' tall grasses, so the butterflies do swarm that area.
The double pinks are lovely on their own, but I have tried planting pink profusion zinnias and pink vinca in front of them. This year I'm trying a pink and white purslane and some stachys 'Pink cotton Candy'. We'll see how that works.
With the red, I have dark blue and purple clematis, and stargazer lilies right in the middle of them. In one area, purple chives invaded, and I let them stay. I might try planting some dark velvety purple wave petunias underneath. Red and white dianthus look great in front of the red roses, also.
One commercial planting in town has Karl Foerster grass behind red Knock Outs, and that's a beautiful, low-maintenance combination.
