In early 1880, newspaper articles throughout much of the English-speaking world, usually headed “for the ladies”, reported that the Paris spring fashions featured a new colour:
LATEST PARISIAN FASHIONS
There is no doubt but that the “heliotrope colour” will take the lead in spring materials, such as silks, grenadines, and wollens [sic]; the peculiar shade is that rosy purple conspicuous in the newly-blown flower, and which the dyers call a “false purple.”
Launceston Examiner (Tasmania), 24 Apr. 1880.
As the writer hinted, there was nothing new about the colour, nor indeed the word. The pretty flower called the heliotrope had long been a favourite in gardens, one that had been chosen as much for its scent as its rich purple colour.
On the face of it, it’s an odd name for the flower, as the helio- prefix refers to the sun and so might be better applied to a shade of yellow rather than purple. Heliotrope has been in the language for about a thousand years, originally in Old English as eliotropus, which had come via Latin from Greek heliotropion for a plant that turned its flowers to the sun. The second part is from Greek trepein, to turn, which appears in the English word tropism for the movement of parts of a plant in response to an external stimulus. One obvious tropism is gravity, which is why roots grow downwards and stems upwards and why plants don’t grow well on space stations. Many plants have the tropism of turning their flowers to the sun — marigolds and sunflowers, for example, as well as heliotropes — and all were at various times called heliotropes. Eventually, for reasons that aren’t clear, the word came to be reserved for the one plant.
The colour called purple in antiquity — often specifically Tyrian purple, because it was made and sold at the ancient Phoenician seaport of Tyre in the eastern Mediterranean — was obtained from a tiny gland in several closely related species of shellfish; about 10,000 were needed to make one gram of the dye. Consequently, it was rare and expensive, reserved for the high-born (hence phrases such as born to the purple). The colour varied between a rich crimson red and a dark purple usually said to be like that of dried blood. The secret of making it was lost in antiquity and the false purple of the newspaper article was one substitute, obtained either from other species of shellfish or by a chemical process involving logwood.
Artificial purple dyes began to appear in the 1830s with murexide, which was made by two German chemists from python excrement; as it’s hard to come by, French chemists later used South American guano instead, of which there was lots. (Incidentally, the German chemists took its name from Latin murex for the shellfish that provided Tyrian purple, though it had never been within miles of one.) Aniline dyes derived from coal tar came next, the first being discovered by accident in 1856 by the 18-year-old William Henry Perkin. He called it aniline purple but later mauveine and mauve (from the French word for the colour of the flowers of the mallow plant).
By 1880, purple fabrics at reasonable prices had been available for more than a decade. It was purely for marketing purposes that the Parisian arbiters of fashion decided to apply heliotrope to a particular shade of pinkish-purple. In doing so, they added a new sense to the dictionary definition of the word, in English as well as French.
Heliotrope was being used more widely at that time for another reason. A substance called piperonal or heliotropine, synthesised in 1869, started to be used a decade later in a perfume said to imitate the scent of heliotrope flowers. It has also been described as smelling like cherry pie, an unsurprising association, as heliotrope has long had the popular name of the cherry pie plant.
The popularity of the word heliotrope continued to grow throughout the last quarter of the century and into the first decade of the twentieth. The fashion for it declined rapidly after the end of the First World War and today it’s relatively uncommon as a word for a colour or scent, though gardeners, of course, still know it well.