Analogous Colours that are harmonious and closely related, such as orange and yellow, red and pink. Analogous colours strengthen and unify a garden colour scheme.
Complementary Two colours that are opposite one another on a colour wheel and provide intensity when partnered. Examples include the hot and cool effects of burnt orange and cobalt blue, or red and green.
Polychromatic A carnival effect, mixing any and all hues together in one eclectic, random scheme.
Monochromatic Colours that are varying shades of the same basic hue. In a monochromatic scheme, such as various shades of pink blossoms, other design elements like texture and form become important.
The vivid hues of hybridized garden plants such as geraniums and impatiens are the result of breeding programs in which genes are manipulated to produce particular petal colorations. But the ancient species ancestors of modern hybrids may have had quite different hues. With a bit of time and patience, you can test this theory by collecting seeds from annual impatiens of any colour in late summer. Save them to grow next spring; then collect the next crop of seeds. After three or four generations, you'll begin to have seedlings in a dominant colour (most likely a dull magenta). This is the original hue of impatiens that once grew in semi-tropical jungles.