Dahlia

Dahlia is a New Latin coinage, created by the Spanish botanist and naturalist Antonio José Cavanilles in 1791, who named the genus after Anders Dahl — a Swedish botanist and student of Carl Linnaeus who had died in 1789, two years before the name was published. Dahl had never seen the plant; his association with it was purely honorific, the common practice of commemorating naturalists through botanical nomenclature. The dahlia is native to Mexico and Central America, where it had been cultivated by the Aztecs for over a thousand years under the name acocotli or cocoxochitl — names that referred to the plant's hollow stems (acocotli combines Nahuatl words for 'water pipe') and its tuberous roots. The Aztec names were discarded; the Swedish naturalist's surname was applied to a flower he never encountered.

In Aztec and pre-Columbian Mesoamerican tradition, the dahlia was valued not primarily as an ornamental flower but as a food crop, a water pipe, and a medicinal plant. The hollow stems were used as water tubes, the tuberous roots were eaten (they contain inulin, a complex carbohydrate with a mild, sweet flavor similar to Jerusalem artichoke), and the plant was associated with religious ritual. When Spanish colonizers encountered the dahlia growing in Mexican highland gardens during the sixteenth century, they initially brought seeds to Europe without understanding the plant's multifaceted role in indigenous culture. The Europeans saw only the flower; the Aztec agricultural and medicinal knowledge embedded in the plant's cultivation was largely ignored.

The dahlia's introduction to European horticulture began in earnest in the late eighteenth century, when the Real Jardín Botánico in Madrid received seeds and tubers. Initial cultivation attempts were complicated by the European climate, but by the early nineteenth century, breeders in France, Germany, and England had developed the dahlia's extraordinary genetic plasticity into hundreds of distinct varieties. The wild Mexican dahlia has eight petals. By the 1830s, breeders had produced varieties with hundreds of petals arranged in ball forms, cactus forms, anemone forms, and decorative forms that bore almost no resemblance to their Mesoamerican progenitor. The dahlia became a breeder's canvas, its extraordinary variability allowing the creation of new varieties at a pace that satisfied Victorian competitive horticulture.

The Royal Horticultural Society's dahlia shows became major events in the Victorian social calendar, with competitive growers submitting specimens judged for perfection of form, consistency of color, and size. The dahlia was uniquely suited to Victorian competitive culture: it was technically demanding to grow well, highly variable across varieties, and capable of being improved through patient selective breeding. Unlike the rose, which required years to develop a new variety, dahlias could be bred in a single growing season by crossing tubers and growing from seed. The colonial plant named for a botanist who never saw it became, in Victorian hands, both a competitive sport and a democratic flower — accessible enough for working-class allotment gardeners to participate in the same shows as aristocratic estate gardeners.