The lily-of-the-valley (Convallaria majalis) is a herbaceous plant from the Liliaceae family. Native from Asia, it is found in the temperate regions of Europe, Asia and North America. Its flowers are very fragrant clusters of small white bells and emerge in early Spring, so it was quickly associated with its renewal; Celts were the first to believe that lily-of-the-valley could bring happiness. The mating system, in conjunction with the spread of clonal propagation by rhizomes, was recently the subject of a study published in Annals of Botany (1). The authors demonstrated a high paternal genetic diversity in the populations studied in relationships with a high rate of outcrossing, thus revealed to be compatible with the maintenance of clonal propagation.
The tradition of giving a sprig of lily-of-the valley on 1st May backs to Renaissance, when Charles IX offered (since 1561) this flower to his entourage, as a good luck for the whole year. We find that traditional gesture in France (including Nantes region, the major production area of thrush in France), but also in Switzerland, Belgium and Andorra. The Latin name of Convallaria majalis gave him the common name of Lys des vallées in French and lily-of-the-valley in English because it literally means “con-valley of May”, that is to say, it grows in May in the valleys.
The first day of May as Labour Day was adopted at the founding congress of the Second International (or Socialist International) in Paris in 1889. During a manifestation in 1890, protesters walked wearing a red triangle symbolizing the ideal division of a 24h-day: work-sleep-hobbies. This triangle was replaced by the wild rose and then, under Pétain, as red was the color symbolizing communism, the white colour of lilies was adopted.
But we should keep in mind that lily-of-the-valley is classified as a highly toxic plant (2) because of the presence of cardiac glycosides, such as convallatoxin, convallamarine or convallarine. These substances have cardio tonic (which slow the heart beat and increase blood pressure) and diuretic properties. It has long been used in herbal medicine and more recently in Pharmacology (3) to cure heart diseases. However better known by its typical perfume, lily-of-the-valley was used from the sixteenth century in perfumery, mainly replaced now by synthetic molecules.
So, today, do not forget the traditional natural perfume of your sprig of lily-of-the-valley, and we wish you all a nice Labour Day!
(1) Vandepitte K, De Meyer T, Jacquemyn H, Roldán-Ruiz I & Honnay O. 2013. The impact of extensive clonal growth on fine-scale mating patterns: a full paternity analysis of a lily-of-the-valley population (Convallaria majalis). Annals of Botany 111(4): 623-628, doi:10.1093/aob/mct024
(2) Löffelhardt W & Kopp B. 1981. Subcellular localization of glucosyltransferases involved in cardiac glycoside glucosylation in leaves of Convallaria majalis. Phytochemistry 20: 1219-1222. doi:10.1016/0031-9422(81)80008-8
(3) Garnier G, Bézanger-Beauquesne L & Debraux G. 1961. Ressources médicinales de la flore française. Paris, Vigot Frères Eds. 2 vol., 1511 p., 37 planches.