Like most gardeners, at this time of year I often buy new plants. One recent purchase was a pretty pink Black-Eyed Susan, Thunbergia ‘Pink Sensation’ and, as it wasn’t in flower, the only guide I had as to the eventual colour of the flowers was the photograph on the label. This happens all the time of course, and I probably didn’t think much about the actual shade of pink of the flowers to come. But an article in the Gardeners’ Chronicle of 3 May 1913 (which I came across recently while researching something else entirely) made me stop and think about the different shades of colour in our gardens, and how they’re described in the horticultural world.
The article in the Gardeners’ Chronicle reported on an RHS Award of Merit given to a small, pretty alpine covered with bright pinkish flowers, Aethionema armenum, shown by Ellen Willmott of Warley Place fame. What caught my attention however, was the additional description of the colour of the flowers as “very pale violet-rose, 154 of the Repertoire de Couleurs”. Intrigued by this, I discovered that the Repertoire was a French colour chart published at the beginning of the 20th century, see here – a forerunner of today’s RHS Colour Chart used worldwide for recording plant colours (more on which later).
I hadn’t really considered that, in the past, shades of different colours had to be standardised and ‘named’, just like the plants themselves. The simplest definition of colour that I’ve found seems to be that “it’s a property of light as seen by people” (simple.wikipedia.org) but, as we know, people often perceive colours slightly differently. For example, scientific experiments show that there are definite differences between the sexes in how they see shades of colour. (There’s a lot of information on this aspect of colour perception on the internet if you wish to know more.)
The Repertoire was not, however, the first attempt to standardise the description of different shades of colour. Aristotle is credited with developing the first known theory of colour believing it was sent by God, and these beliefs were widely held for over 2,000 years until Sir Isaac Newton’s experiments with light in the mid-1600s. Newton discovered, as we were taught at school, that a beam of light could be split into a spectrum of different colours by passing it through a prism. And it was also Newton who later produced the first rudimentary type of colour wheel.
Many works on colour followed, until the late 18th century when German mineralogist, Abraham Werner, devised a standardised scheme for classifying colours later adapted and revised in the 19th century by Scottish painter, Patrick Syme, published under the title Werner’s Nomenclature of Colours with additions by Patrick Syme (Flower-Painter, Edinburgh) in 1814. Syme enhanced Werner’s original guide by including painted swatches for each colour based on Werner’s precise descriptions, and examples of where to find the colours in the natural world.
In the book, Syme summarised the problem of the lack of standardisation in colours:
“A nomenclature of colours, with proper coloured examples of the different tints… has been long wanted in arts and sciences. It is singular, that a thing so obviously useful… should have been so long overlooked.
To remove the present confusion in the names of colours and establish a standard that may be useful in general science, particularly those branches, viz. Zoology, Botany, Mineralogy, Chemistry…is the object of the present attempt.”
Werner’s guidebook served as one of the best guides for colour classification of the time and Charles Darwin is even said to have consulted it for reference during his voyages on HMS Beagle while researching natural history.
The next major colour classification work was the Repertoire, published in 1905 by Rene Oberthur and Henri Dauthenay – its full title translating as ‘Colour directory to help determine colours of flowers, foliage and fruits’.
Coincidentally, there’s an exhibition on the subject of colours in nature at the Royal Botanic Gardens, Kew until 6 September. Entitled Nature’s True Colours, it explores the need by botanists and mycologists for standardised colour terms for the precise identification of plants and fungi when working both in the field, and with dried, pressed specimens. For more information on the exhibition and various other early colour systems see here.
And so to the RHS Colour Chart: first published in 1938 in order, according to the scientific journal, Nature, to “meet a pressing need” to update previous standard works on colours which were either out of print or too expensive to have a wide application (Nature, 138, 1936). This first chart consisted of just 100 loose plates of printed colour samples. The RHS chart is now updated every few years and the latest, the sixth, was published in 2015. The RHS describes its chart as “the standard reference used by horticulturists worldwide for recording plant colours. Resembling a paint chart, it has 920 colours which can be matched precisely to flowers, fruits and other plants in order to record and communicate colours accurately across the world. Each colour has a unique number and letter code as well as a name”. The chart is also used in industries such as food, cosmetics, pharmaceuticals and fashion.
I’m not about to splash out £199 on an RHS Colour Chart and check all the shades of colours in my garden, but I did check my new Thunbergia against the Repertoire and, somewhat to my surprise, the nearest match was ‘pale violet-rose, 154’.
There are, of course, many articles and books about using colour in our gardens. Perhaps the most famous recent promoter of being bold with colour was Christopher Lloyd of Great Dixter (fame with his book Colour for Adventurous Gardeners (2001) – its first chapter entitled, ‘Colour. Go for it!’. More recently, Gardeners’ World presenter Nick Bailey’s book, 365 Days of Colour in your Garden (2015) covers the “infinite variability of plant colour in gardens” with chapters on ‘The Art and Science of Plant Colour’, and ‘The Colour Wheel for the Gardener'. As he writes, “colour is such a joy to experiment with… the possibilities are endless”.
After all, you have 920 shades to play with!