Both of these are marigolds, but are in fact very different plants. Tagetes patula (left) and Calendula officinalis (right).
Common names for plants aren’t really all that common, are they? At least, not common to all gardeners. The same plant can go under dozens of names around the world, not only in different languages (it’s practically a given that every plant has a different name in each one!), but even within a single language. So, if a friend talks about a plant using a common name, they may not be discussing the plant you think. That’s why serious gardeners learn to use the botanical name of their plants: it’s the same all over the world.
The marigold is a case in point. As you saw the word marigold written on this page, your brain probably filled with an image of the plant that you know as marigold. But different people would see very different plants.
In my case, the word “marigold” brings up an image of Tagetes patula (French marigold) and perhaps T. erecta (African marigold), although in fact these plants are neither from France nor Africa, but the New World, introduced to Europe in the 1500s. And they didn’t really become common garden plants until the 20th century. That’s the plant I knew as marigold as a child and for many English speakers, either of these species, or some other species of Tagetes, like T. tenuifolia (signet marigold) is the “true marigold.”
But, as the song says, it ain’t necessarily so.
The original marigold was in fact Calendula officinalis, a plant I knew as calendula and, alternatively, pot marigold. An annual wildflower native to Europe, it became known as Virgin Mary’s golde (for its golden-yellow flowers), eventually shortened to marigold, sometime around the time of the Norman Conquest (1066). In many parts of the United Kingdom, C. officinalis is still the marigold, although in others, gardeners have adopted the new Tagetes species as their marigold.
Confused? Well, that’s not all. Just about any yellow, daisylike flower, recalling the original Calendula officinalis, is likely to be called “marigold” in some part of the English-speaking word.
Here are a few others:
- Cape marigold (Arctotheca calendula and Dimophotheca sinuata)
- Corn marigold (Glebonis segetum, formerly Chrysanthemum segetum)
- Desert marigold (Baileya multiradiata)
- Marsh marigold (Caltha palustris)
- Tree marigold (Tithonia diversiloba)
Most of the time, this kind of confusion is fairly benign, but using common names can have unfortunate consequences. Like when you order a plant from a source that gives only the common name, then receive something quite different from what you expected. And people have been poisoned when common names have led them to eating the wrong plant.
So, you can see why, when I write about plants in this blog, I may give a common name (or two or three), but I pretty much always back it up with the botanical name. That way, everybody understands what I’m writing about.