In the past, we have touched on the subject of colour theory (including a pdf download from using theories presented by Johannes Itten to try to illuminate one of the more important design elements that has to be dealt with by every gardener. I have recently bought another book on colour (Color in Garden Design, Sandra Austin, The Taunton Press 1998, 165pp) that deals with this complex issue from the specific perspective of the gardener or garden designer. Ms. Austin references her colour theories to elements of culture and design that are relevant to us as we plan our gardens but which often seem to be difficult to control when considering compositions and associations with the bounty of nature and associating them with the colours of hard-surfacing and garden furniture that are equally a part of the garden.

She explains her observations using the Munsell Color-Order System, described in the excerpted introduction (and illustrated by the artist’s colour circle excerpted from the book), to organize the three main attributes of colour (under the Munsell system). These are:

Hue – a colour’s position on the colour spectrum, such as red, yellow or green – it’s base colour

Value – the brightness, lightness or luminosity of a colour – a light or dark quality – can be compared using a greyscale

Saturation – a measure of the colour content or strength of a colour – also called intensity, purity or brilliance – pure hues are the most saturated, greys the least – called Chroma in the Munsell system

The book was an enjoyable read and definitely informative, tying together the various combinations that can be utilized from the above three main qualities of colour to take control of your design efforts. I feel that I now have a somewhat firmer grasp of the hoary conundrum that is colour and will be returning to the book in order to strengthen my understanding.

Here then, are a few pages from the book – a section on colour names as well as a short section on warm colours with notes on the ability of warm and cool colours to effect impressions of depth and distance (perspective), something I had touched on in the above linked essay but had thought to be due simply to colour rather than warmth or coolness.

The colors of an artist’s color wheel do not correspond exactly to the colors of the visible spectrum. The artist joins the two ends of the visible spectrum to form a circle, filling the gap with purplish colors. This produces a useful tool for analyzing color relationships.

Pink impatiens and green coleus leaves – the words lead you to expect to see warm-colored flowers against cool-colored foliage, as in the first set of color samples. But because the pink is a cool pink (it has purple or blue in it) and green is a warm green (it has yellow in it), what you see is closer the second set of samples. The combination strikes an unexpected balance.

Jim Thorleifson

Color in Garden Design

Sandra Austin

The Taunton Press 1998


If you have tried to describe the color of a flower to someone who hasn’t seen it or tried to imagine a plant catalog’s description of the color of foliage, then you are familiar with the problem of accurate color description. This problem has two parts. The first is the lack of precision in color descriptions. For example, what does blue mean? It is used to describe the leaf of a hosta such as ‘Blue Cadet’, and it is also used to describe an impatiens such as ‘Accent Lavender Blue’. If you order these plants our of a catalog, expecting something blue, you might be surprised or perplexed to find that the hosta looks green and the impatiens looks pink. Especially if you put the plants next to a piece of blue paper or look at them next to blue sky, you will feel that neither plant should be called blue.

The second part of the problem is trying to describe the relationship of colors to each other. How could someone imagine that blue is in both green and pink? You can see that if you place a hosta like ‘Blue Cadet’ next to one like ‘Green Fountain’, it does look somewhat bluish, and you can also see that ‘Accent Lavender Blue’ does look bluish if it is next to ‘Accent Pink’ or ‘Accent Scarlet’ impatiens. Perhaps you can sense this relationship, bur don’t know how to explain what you see, much less define it or categorize it.

Artists and designers have faced these problems for a long time, and know that to use color competently, they must understand color relationships. So over the years, they have used various color ordering systems, trying different systems to get closer to a good working knowledge of how to use color.

Color systems are groups of specific colors that have two purposes: to provide a reference standard for matching colors and to organize color relationships. These two purposes are directly related to the problems just discussed. Matching the color of the hosta to a color-system standard will allow you to describe its color more accurately than you could ever do in words; and placing the color of the hosta within an ordered presentation of colors will help you understand how its color relates to other colors, for example, whether it is more blue than green.

Because artists and scientists use color in many different ways, different color systems have evolved. The proliferation of systems reflects the important fact that color does not always act in the same way. Color in light and color in paint do not react in the same fashion, and color as seen by your eye is an even different issue (although there are enough similarities to make the whole issue confusing). One source of confusion is that there are systems that are called color systems but are actually colorant systems, that is, systems that explain the possible results of mixing specific pigments or dyes. These systems are not based on observation of color, but on percentages of different colorants needed to achieve certain effects, such as adding three parts white to one part red to create pink.

This book talks about three color systems and one colorant system. The Munsell Color-Order System and the Royal Horticultural Colour Charts are two that gardeners know and have used to match flower, foliage, and soil colors to color chips. To a lesser extent, these systems have been used by designers, but for most designers, they have not been the reference that they are in some other art fields. The colorant system is the one used in the printing of this book, a system based on mixing inks to be placed on paper. All three of these systems may be explained and standardized through the CIE system, an international standard for color.

If you are confused, remember this: Color and colorant systems are simply different people’s ways of explaining what they see and how they relate the colors to the work that they do. It will always be difficult to use words and printed images to describe what is seen in nature, and no two people will look at a complex scene like a garden and see the same colors. The best advice to the beginner is to learn about the strengths and limitations of these system, and apply what is appropriate to your specific color problems.


The Munsell Color-Order System is an American classifying system that is used as a standard for color notation in artistic, commercial, scientific, and educational work. Developed by an artist, Albert Munsell, for use by artists and designers, it can be used to specify colors and show the relationships among colors. The Munsell system defines a color in terms of three qualities or attributes: hue, value, and chroma. Gradations of color are based on the way people see, not on formulations of paint or other colorant mixing, so that the color of any surface can be identified by comparing it to color chips that are arranged according to steps of visual discrimination.

The Munsell system, acknowledging that color relationships do not fall in equal steps, expresses color relationships as an irregular sphere. The sphere has the pure hues or colors such as red, blue, green, and yellow around its equator. As the colors move toward the core, they become more gray, or decrease in chroma. The vertical axis of the sphere is a neutral gray scale, showing the attribute called value; it progresses from black at the bottom to white at the top. By dividing the sphere into vertical, horizontal, and radial planes, any color can be located in relation to others, and given a numerical reference. Color chips are presented in charts. Each chart is formed from a vertical slice of the sphere, representing a single hue or color and its value and chroma steps-it’s a useful presentation for a designer wishing to compare colors.

One difference between the Munsell system and other systems you may know is that Munsell based his system on 10 basic hues so that the finer discriminations between hues could be described with decimals. Most artist’s systems are based on six hues; the difference is in the naming and the steps, though the basic colors exist in all systems.


The Royal Horticultural Society (RHS) Colour Charts are an English classifying system for flower color. The charts show the three attributes of color: hue, brightness (Munsell’s value), and saturation (Munsell’s chroma). The charts were derived from the Munsell system; you can match Munsell values to the RHS colors, but they do not appear in the same order. In the RHS system, the colors are arranged by color hues except for the strongly desaturated (grayed) colors. There are four color groups: the yellow to red group, the red to blue group, the blue to green group, and the grayed colors. The grayed colors include the grayed variations of all the hues in the other three groups plus browns, but are not directly related in the system to any particular hue. Color names found in the early versions of the system are no longer used; the colors are classified by letter and number groups.


Color names such as vermilion, verdigris, apricot, and salmon, which are so evocative and pleasurable in writing and speech, can be exasperating when you are trying to be precise about color. If you think the basic color vocabulary of red, green, yellow, and blue is as clear as black and white, you may change your mind as you read this chapter, which deals with the way we describe the colors of the rainbow, as well as white, black, and gray.


When people look at a rainbow, they name the colors red, orange, yellow, green, blue, and violet, as the colors appear from the top of the rainbow. These colors are called chromatic, or spectral, colors, and each color name represents a band of colors that fall within a recognized range. People rarely think about the different colors represented by the name “red” unless they need to match a specific red, such as the red in a rose. It is then that they begin to realize how limiting color names can be.

If you are looking at a representation of the visual spectrum and trying to name the colors you see, you notice some things that may strike you as unusual. When you see the colors arranged in a band (as they are in the spectrum on the facing page), you notice that the color called violet is most physically unlike the color called red; they are, respectively, the shortest and longest wavelengths. Furthermore, you can’t even find anything that looks like purple or reddish purple, even though you have always considered it a rainbow color.

Artists care about how colors relate in appearance, so they choose to display color information in a circular form that seems to makes more sense in terms of how color is seen. The spacing in a color circle is regular, rather than uneven, as in the spacing of the chromatic bands, so the color names fall in a regular sequence. The reds, purples, and violets that may be different in terms of wavelengths appear similar in human vision, and so the color circle bridges this gap to complete the circle. The color wheel appears to describe a very natural progression of colors.

Because of the confusion in even the simplest of color names, most color systems, including the Munsell and the RHS systems, now describe intermediate colors with number and letter designators, instead of color names. While you may prefer to identify an artemisia as gray-green instead of7.5GY 5/2, there is a real advantage to having specific color designations when needed.

Gardeners deal not only with common color names, but with botanic names as well. Often botanic names refer to perceived color, using words that may no longer have a popular shared meaning and may include other attributes such as texture (candicans implies not only a white color, but a woolly texture) and form (albomaculatus means having white spots, albispinus means white spined). In a general sense, these names will give you clues about a plant’s appearance, such as being more reddish or greenish, but not precise color information.


White, black, and gray are achromatic (having no hue), or neutral.

Think of white and black in the following ways:

In human vision: They are colors because they arouse sensations.

As light: White is not a color, but the sum of all radiations; black is the total absence of light.

As paint: White is a primary pigment; it cannot be obtained from other colors; black is a secondary pigment because it is mixed using other colors.

White is the lightest color; black is the darkest. But as a practical matter, there are rarely absolute whites or blacks, just as in the garden, there are not true white or black flowers or foliage. When you look closely at white in the garden, you can almost always discern a secondary or underlying color in the eye, bud, or petal of a flower, and with practice (and a glossy piece of white paper for comparison) you can see the color gradation (yellowness, greenness) of the white. Upon close examination, you can almost always identify the true color or colors. This is just as true for black-black flowers and foliage are found upon close examination in clear light to be blues, purples, and greens, darkened nearly to the point where they lose their color identity and are referred to as black.

Other than flowers and foliage, you can talk about seeing white and black in other places in the garden, although it is more accurate to say that you see light and dark colors. Haze and fog cast a whitish film over objects, and the yellowish-white glare of a hot summer’s day bleaches out many colors. Snow and ice can have a bluish cast from the reflected light of the sky, or a yellowish-white glare from the sun. Both white and black are common colors for garden furniture and furnishings such as fountains, fences, and lattice work. Black appears to be seen in shadows and shade, again showing a bluish cast from the reflected light of the sky, or some other color from the light reflected by nearby objects. Finally, as evening approaches and light in the garden decreases to the point where the eye can no longer discern colors, you see your surroundings in terms of near-blacks and whites and the gradations in between.

Think of gray in the following ways:

As light: Gray colors are produced by reducing the intensity of white light.

As paint: Very dark gray or gray-black can be achieved by mixing varying amounts of black and white or two complementary pigments (such as violet and yellow).

Grays in the foliage and flower garden are not true grays, but most often pale yellow-greens, such as lamb’s ears and artemisia, and pale greens and bluish greens such as some sedums and blue fescue. Certain textural characteristics-small hairs or wax-reflect surface light and cause the graying aspect of these plants. Their color is changed by weather and temperature conditions, often appearing more green or blue in winter, in shade, just before bloom, or when wet. The bark of trees and shrubs is a darker reddish or yellowish gray, such as the reddish gray of flowering cherry. The underlying color becomes apparent only when you hold a true achromatic gray next to the object.

When you look at a distant landscape, you often describe the objects far away as being gray or blue-gray. Pollution can give haze and fog a grayish or yellow-gray cast, which throws a film over all but the closest objects. Grays also describe many weathered objects such as wood, as well as stone colors, which have a wide range of underlying colors from yellows and reds to blues and purples.


Through the years, artists and designers have tried to find regular or mathematical spacing in color systems that would lead them to beautiful color harmonies. Some of these relationships evolved during times when artistic goals were different from modern sensibilities and were based on theories of color vision that have been proven false. Nevertheless, these relationships are still being used as a starting point for developing color combinations.


Warm and cool are terms that describe relative sensations for two groups of colors. The warm hues are red, yellow, and magenta or red-purple, with the warmest generally in the red area. Colors that have red in them are generally recognized as being warm in character. Warmth describes a non-visual sensation, but most people have no difficulty understanding the concept and relating it to the color of things they are familiar with, such as fire and the sun. Descriptive terms – hot pinks, fiery reds, sunny yellows – often reflect this apparent relationship.

When gardeners discuss warm and cool colors, such as bright orange flowers against a deep-green hedge background, the comment is made that warm colors advance (appear closer) and cool colors recede (appear farther away). One reason may be that the eye focuses differently when it looks at red than when it looks at green or blue. This refocusing is similar to what happens when the eye looks at objects that are near and far. The eye may focus on red and nearby objects in a similar fashion and on blue and green and far-away objects in a similar fashion. So your eyes feel at rest when you view objects in the distance, as they do when you focus on blue and green. This may account for the idea that green and blue are restful colors.

The apparent ability of warm and cool colors to create different dimensions of distance and depth (sometimes referred to as a color’s kinetic ability) is complex, particularly when you start to combine hues of differing values and saturations. Each color has a cool and warm range; that is, for the warm colors, yellow has a warm range moving toward orange and a cool range moving toward green; orange has a warm range moving toward yellow and a cool range moving toward red; and purple has a warm range moving toward red and a cool range moving toward blue. So an orange can appear cooler than a purple, depending on the specific hues involved.

For each of these hue ranges, there is also a range of values (light and dark variations) and a range of saturations (grayed colors). Colors of high value, no matter what the hue, may appear to be closer than medium and low values of the warmest colors. A purple flower, catching the light, may appear lighter and therefore closer than its green foliage. Colors of high saturation, no matter what the hue, may appear to be closer than grayed warm colors. A clear green may appear closer than a medium brown.

Because of the way the eye sees color, people can recognize red, orange, and yellow as warm colors, but may have difficulty deciding whether green-yellow and purple are warm or cool colors. The visual signals for the last two colors may vary, depending upon whether there is more yellow or green, or more red or blue, apparent in the hue. Green-yellow foliage with a purple-pink flower may send mixed visual messages; so it may not always be possible to predict whether a warm color will advance, even if it is next to a cool color.

Warm colors are used for reasons other than their ability to stretch or contract distance. Many people do think they feel warmer in the presence of yellow, red, or magenta, and so in a cooler climate or during cooler times of the year, these colors may be used to heat up a garden. Think of gardens outside living-area windows during early spring and late fall and winter, and imagine the impact of the warmer colors, whether they are yellows and oranges in spring bulbs or yellows and reds in autumn leaves.