Ceratostigma plumbaginoides 'AUTUMN BLUE' leadwort, hardy plumbago

Ceratostigma

The genus Ceratostigma, commonly known as leadwort or hardy plumbago, belongs to the Plumbaginaceae family and comprises just seven accepted species distributed from eastern Africa through the Himalayas to China and Indochina. The genus was established and scientifically described by Alexander von Bunge (1803–1890), a Russian-German botanist who collected numerous plants previously unknown to European science during his expedition to northern China. The name Ceratostigma itself is derived from the Greek words for horn and stigma, referring to the tiny horn-like projections found on the stigmas of the flowers and visible only upon close inspection. While the origin of the common name leadwort remains debated, one theory links it to the grey-blue colour of lead, while another traces it to traditional medicinal uses of plants in the related genus Plumbago, which were once recommended for ailments associated with the then-common effects of lead poisoning. Despite its modest size, the genus includes a remarkably diverse range of plants, from ground-covering perennials to mountain subshrubs inhabiting rocky slopes, woodland edges and alpine valleys across Asia.

The species Ceratostigma plumbaginoides was described by Alexander von Bunge (1803–1890) in 1833 from plants collected during his expedition to northern China. At the time, the region around Beijing remained only lightly explored botanically, and each new collection had the potential to contain species unknown to European science. This species became the type species of the newly established genus Ceratostigma and remains its best-known representative today. Its journey into European gardens, however, was far from straightforward. The celebrated plant collector Robert Fortune (1812–1880) encountered it during his travels around Shanghai, yet his early attempts to introduce it into cultivation were unsuccessful. It was not until 1846 that living plants were sent from Canton to the British merchant Sir George Larpent, where they flowered later that same year in his garden near London. The novelty appeared so unusual that it was briefly described under the new name Plumbago larpentae before botanists realised that it was the very species discovered and named by Bunge several years earlier in northern China.

Incidentally, did you know that blue was among the rarest and most prized colours throughout much of human history? While red, yellow and brown pigments could be obtained almost everywhere, producing a rich and lasting blue was considerably more difficult. Among the most valuable sources were indigo dyes extracted from plants and the precious stone lapis lazuli imported from what is now Afghanistan. The high cost of blue pigments meant that blue garments, textiles and decorative features served for centuries as symbols of wealth and status. In medieval Europe the colour gained further prestige through depictions of the Virgin Mary wearing a blue cloak, and its popularity was strengthened by King Louis IX (1214–1270) of France, who adopted it among the symbols of royal authority. Only towards the end of the nineteenth century was the chemical nature of indigo fully understood and industrial production established, gradually transforming blue from a luxury commodity into an everyday colour.