No founder, organization, proclamation, or campaign for the May 20 Flower Day has been documented. The day circulates through holiday listings and social posts as a general appreciation of flowers, and there is no sourced explanation for why it lands on May 20.
A language assembled from imagination
The idea that flowers could speak reached Europe through Lady Mary Wortley Montagu, who described Turkish flower-message customs after living at the Ottoman court in Constantinople around 1717. Her letters seeded a fascination that would bloom a century later.
The first real reference book came in 1819, when Louise Cortambert, writing as Madame Charlotte de la Tour, published Le langage des Fleurs, the first dictionary of floriography. An earlier 1809 list by Joseph Hammer-Purgstall had catalogued meanings, but Cortambert's book set the template. By mid-century the genre had become a fixture of Victorian bookshelves, and Victorians traded small bouquets called nosegays or tussie-mussies as wearable notes.



