The most common harmonies in the garden are derived straight from art color theory: monochrome, complementary, triadic, and analogous.

The monochrome scheme is pretty straight forward. Same color, same hue. Everywhere.

The complementary scheme is one of the most used in professional landscaping, because it is easy to achieve with both perennials and annuals and remains stable for many years. Classic examples include the day lily and Russian sage combination, or tick seed and hostas. It brings together complementary colors: cone flowers and black eyed Susans, plumbago and goldenrod, calendulas and delphiniums. Variations on this theme split one or both of these colors into two different shades.

The triadic scheme uses three colors that are at equal distances on the color wheel: green, orange and purple, yellow-green, red-orange and blue-violet, you get the idea. If your garden seems to be missing something, check the colors you already have in it and pull out the color wheel. You’ll be surprised what the color accent should be. You’d never guess, for instance, that what your subdued pink and blue flower garden is missing is phosphorescent yellow green.

The analogous scheme consists of using three of four colors that are next to each other on the color wheel. This is another design that is very popular, because it is easy to create and easy on the eye, if you want something that looks pretty, but will be more of a background and not compete for your attention. Analogous color schemes tend to be very soothing. Rose gardens and public parks often feature analogous schemes. The flowers are planted in drifts, not mixed, to create solid blocks of color. Good combinations are red-orange-yellow, pink-magenta-violet, blue-violet-purple-magenta. The pink-magenta-blue scheme often emerges naturally in cottage gardens, whose flowers tend to sport these colors.

Last, but not least, there is no such thing as incompatible colors in garden design. If the color combination appeals to you, by all means use it, color theory or not.

Author's Bio: 

Main Areas: Garden Writing; Sustainable Gardening; Homegrown Harvest
Published Books: “Terra Two”; “Generations”; "The Plant - A Steampunk Story"; "Letters to Lelia"; "Fair"; "Door Number Eight"; "A Year and A Day"; "Möbius' Code"; "Between Mirrors"
Career Focus: Author; Consummate Gardener;
Affiliation: All Year Garden; The Weekly Gardener; Francis Rosenfeld's Blog

I started blogging in 2010, to share the joy of growing all things green and the beauty of the garden through the seasons. Two garden blogs were born: and, a periodical that followed it one year later. I wanted to assemble an informal compendium of the things I learned from my grandfather, wonderful books, educational websites, and my own experience, in the hope that other people might use it in their own gardening practice.