My earliest education on color harmonies in the garden was influenced by seeing gardeners passing along plants to each other, tucking the plants into whatever spot was available, and admiring (and unashamedly bragging on) the individual color when each plant was in bloom. When I got my own place, I decided to be a little more uppity about the placement of plants. Landscape design has its appeal, even if it doesn't come naturally to me. I planted white spirea beside the red Japanese maple. I put pinks and whites and blues together. I put a yellow daylily by the purple coneflowers. You get the idea.
However, despite all my effort for harmony, I ended up with daylily 'Final Touch' blooming next to phlox paniculata 'Robert Poore.'
As Daddy would say about things that don't go as planned, "Ain't THAT a sight?"
But, there is no doubt a way to appreciate the colors together, and I think I've found a way. Years ago I bought a book, The Perennial Garden: Color Harmonies through the Seasons by Jeff and Marilyn Cox. I enjoy referring back to it from time to time. In the section on color harmonies, they describe a particular perennial bed which borrowed its color scheme from a Henri Matisse painting. If you look up Henri Matisse on the internet, you will notice descriptions about his use of color which include words like expressive, dissonant, and unmodulated. The garden bed in the example had red and hot pink dianthus next to lavender dianthus and "fleshy apricot" iris which, in turn, was next to dark burgundy iris which was flanked by blue and white aquilegia. There you go! Now, whenever I see my pink and yellow daylilies (which from a distance look peachy) next to the hot magenta phlox, I lift my chin a little higher and whisper to myself, "reflections of Matisse."
Of course, if I had to tell you my personal favorite color, I'd probably adapt a line from a folk song and say "greens and blues are the colors I choose," though at times I am loath to narrow it down. I saw this blue damselfly on a blade of green grass in the garden yesterday. Now that is a pretty color scheme if I ever saw one!