When poinsettias appear in the stores, it’s a sure sign that the festive season is upon us. But why are these Central American natives such an iconic symbol of the season in our country? And (perhaps more to the point, for our purposes) who pollinates them?
Poinsettias were extensively used in their native land by Aztecs for both practical and magical purposes. Later, Franciscan priests in southern Mexico utilized the flower’s brilliant red and green colors to decorate their nativity scenes, and this became a tradition throughout Mexico.
Poinsettias (Euphorbia pulcherrima, meaning ‘most beautiful euphorbia’) were introduced to the US after 1825 by Joel Poinsett, the first US ambassador to Mexico. A keen amateur botanist and proponent of using science to improve agriculture, he sent cuttings to his greenhouse in South Carolina for propagation. However, it wasn’t until the 1920s that California nurseryman Paul Ecke Sr. developed a cultivar that could be successfully grown as a houseplant.
But what of pollinators? What we consider the petals of a poinsettia ‘flower’ are actually modified leaves (bracts), and the tiny yellow centers are the actual flowers that contain the goods, nectar and pollen. While both male and female parts are borne on each flower, they don’t mature at the same time (protandry). The male part of the flower goes first, its stamen releasing pollen. As it begins to shrivel, a single female flower emerges. So poinsettias can fertilize each other, but as with so many plants, it’s much better with a little help from their friends!
It has long been assumed that birds, especially hummingbirds, are principal pollinators of poinsettias in the wild, owing to the flowers’ bright red color. However, according to ecologist and author Jeff Ollerton, these assumptions may not be accurate. Personal observations in a garden setting in China revealed many ants pollinating the flowers, along with some interested Asian honey bees. It seems incredible that so little is known about such a ubiquitous holiday favorite–but until much field research in Mexico is done, we can only guess.
Happy holidays from the SBG!
