It?s interesting to read Trevors comments on colour and all the responses. Colour is something I have been closely associated with in my career, so here are my comments. It is a subject which is potentially very complex but it needn?t be from a gardening point of view. The most practical reference for identifying pleasant combinations and avoiding colour clashes is the colour wheel or circle as mentioned by Trevor and illustrated on the website he refers to. Guides on choosing colours advises the use of adjacent colours to create harmony, colours at 120 degrees to create contrast, complimentary (opposite) colours for drama/vibrations/excitement. Often the odd splash of complimentary colour amongst a format of harmonising colours creates a pleasing result, especially in home decorating. In a garden environment, a splash of ?Lucifer? amongst of a bed of green and pastel colours has the same effect. Black and white may of course be used in any combination and should be regarded as part of the colour palette. In practice a colour is defined using three attributes: hue, saturation or value, luminosity or intensity. Colour harmony is more clearly achieved if these factors are understood.
Hue is the attribute which answers the question ?What colour is this??
Saturation answers the question ?How is it coloured??. Pink and red, for example are the same hue but pink is less saturated than red, ie it contains a smaller amount of the red hue.
Luminosity represents the sensation of light and dark given by each colour in its own particular way in relation to the intensity of the light that illuminates the object. See picture for guidance.
A good rule of thumb on colour harmony in addition to those above, is for one of these attributes to be roughly the same. For example, we all know that pastel shades harmonise irrespective of colour ? this is because they have the same degree of saturation. A bright red flower harmonises with pinks because they are the same hue. It is difficult to find an example of constant luminosity in the garden but look around at company logos on adverts or vehicles ? some of them use unlikely colour combinations but are often of low but constant intensity and it works. Having said all that, nature breaks all the rules and gets away with it. I could go on but don?t want to be boring. As ? says there are lots of web sites and books to be found, even specifically on colour in the garden. The latter talk about ?effects? such as bright colours bringing things closer, pastels giving distance. How the light source can change colours ? my garden takes on a different mood in twilight, the greens and yellows being much more vibrant. The other topic which I won?t go into is the difference between additive and subtractive colour mixing, however if you intend to use coloured lights in your garden it is worth studying this aspect.