Steve, when I lose a crucial piece of a design, I place a piece of pottery, or a chair or birdbath, or tower, or gazing ball or something else in there until a new plant can be added. Sometimes I end up leaving the item. Your touch of color doesn't have to be a plant, but if you want red, daylilies come to mind. Many of the red ones bloom for 8 weeks or so. Well here they do, not sure about AZ.
I have some blue glazed pots that really come in handy in the flower beds. Seems like that color goes about anywhere. Long ago, my kids pulled an old wooden lawn chair out of the trash and painted it green. (and purple, and pink, but it's green now). it looks pretty good in the garden, and I find myself sitting there, taking breaks, more and more. One of my little dumpster divers will be coming home in a few weeks after she graduates, (while she searches for a job) and I might put her to work painting chairs. Doesn't DD stand for Dumpster Diving Daughter?
One of the rose beds has yellow roses, tall grasses, yellow and purple baptisia, caryopteris, russian sage, salvia, amsonia, iris, and a backbone of tall shrubs and arborvitae. I tried adding a touch of orange and then red, and didn't like either one. There is a dark red smoke tree in the back, so maybe that's all the contrast it needs. Yellow and purple, IMHO, are the perfect combination.
Having said that, I do have a bed with red roses that have dark purple clematis runnning through them and Homestead purple verbena and red petunias as groundcover. I like that combo too, but it's kind of hot. The yellow- purple is calming and feels more natural, so I have it near where i sit in the evening. The yellow and purple plants I have are also very xeric. If I don't water the red roses enough, their color doesnt' hold up well.
