Sunday, October 16, 2016

Plant Confusion -- Marigolds and Calendulas

The marigold has conquered the world. Marigolds are common enough that we don’t pay them much attention. Look: marigolds in Bali:

marigolds, Ubud, Bali, Indonesia

and Taiwan
marigolds, Taipei, Taiwan
marigolds, Taipei, Taiwan
In Asia, they are very much loved...and a long way from home.

Marigolds are a group of about 55 species in the genus Tagetes, sunflower family, Asteraceae. They are native in the Americas, from New Mexico in North America to southern South America.

marigold, Tagetes
marigold, Tagetes 
They were important ceremonial flowers among the Aztecs. Like many other newly-discovered American plants such as chilis and bougainvillea, marigolds were transported to the Old World tropics in the early 1500s. The tall Tagetes erecta came to England from North Africa and the smaller T. patula, from France, hence the names African marigold and French marigold respectively, that were used by Gerard in his 1599 herbal (Gerard online) and have been their names generally in English since.

marigold, Tagetes
more marigolds (Tagetes)
But the name marigold was already in use in England when these plants arrived. The plant the English usually called a marigold was a yellow or orange flower from southeastern Europe, scientific name Calendula officinalis (sunflower family, Asteraceae). There were other marigolds in England. The name referred to the Virgin Mary, and after the Reformation, England's Queen Mary, and gold or a golden flower, and was easily given to a variety of orangy flowers, for example marsh marigold (Caltha palustris) and corn marigold (Glebionis segetum). But the calendula was the one most people called a marigold.

pot marigold, Calendula officinalis
pot marigold, Calendula officinalis
Upon arriving in England, the new marigolds grew easily and became very popular. As they eclipsed the earlier marigold (Calendula), people started calling the Tagetes species simply marigolds and the Calendula species had to be called pot marigolds (reflecting that they were used as a vegetable or that they were grown in pots) or calendulas in order not to confuse them. Pot marigold was the most common name used for calendulas over the last 500 years but I have taken calling them calendulas because it more clearly separates calendulas from marigolds (Tagetes).

French marigold, Tagetes patula
French marigolds, Tagetes patula
Marigolds and calendulas are confused a lot.

Calendulas are universally agreed to be edible. (From here down, I'll write calendula and occasionally pot marigold for the genus Calendula and marigold for the genus Tagetes).

Marigolds have a more mixed reputation. You can read "eat" and "don't eat" online. Let me cut to the chase and then express my concerns.

Reputable websites describe recipes for marigolds (linklink). An expensive technical book by T. K. Lin on edible and nonedible flowers indicates that the three commonly-grown species of marigolds (T. patula, T. erecta and T. tenuifolia) are edible (link: You can see the first two pages for each Tagetes species in the sample pages.) The other 54 or so species of Tagetes may or may not be edible: Foster and Johnson say many are toxic and "should not be consumed in any form" (p. 75).

Marigolds are widely used in companion planting, putting them around vegetables to repel garden pests above and below ground (link). They contain compounds that are effective nematode and insect poisons. In the United States, marigolds are approved as food for chickens but not people (contrast the regulations: U.S. F.D.A.: calendula U.S. F.D.A.: marigold) and have some known toxicity to dogs (link). In the early 1900s, Burpee seed company bred lots of diverse marigold varieties, including some that were "scentless" (link), suggesting the chemical make-up of marigolds can be pretty variable. Kelly Berry at said it well: there are toxins in marigolds but they are not very dangerous to humans (link). Probably the best advice to eat them if they taste okay to you and if they don't, skip them.

African marigolds, Tagetes erecta
African marigolds, Tagetes erecta
Both marigolds and calendulas are good dye plants and the color of the flowers, fed to chickens, intensifies the yellows in eggs and in the flesh of the chickens.

What made me concerned researching marigold edibility was that most people writing online that marigolds are edible don't seem to know the name is ambiguous. Looking more carefully, I found most of the print literature on edible marigolds refers to calendulas, under the name pot marigold. For decades, I've collected plant books, so I dug through my library. I found that the pre-internet herb and edible plant literature talks about eating pot marigolds, that is calendulas, and says almost nothing about African marigolds or French marigolds. (The complete list of the books I looked in and what I saw is given at the end of this post, after the References.)

Of 26 herb/edible flower/garden flower books in my library that talked of Calendula as an herb or edible plant, only eight mentioned Tagetes and only four of those said anything about eating them. Before 1974 nobody mentioned Tagetes at all, they wrote about pot marigolds (Calendula). Thus, the edible marigold in the printed literature of the last century is almost always the pot marigold Calendula. There is very little information on eating the plants we now call marigolds.

marigolds, Tiananmen Square, Beijing, China
marigolds, Tiananmen Square, Beijing, China
In the online literature, generally when you type marigold you get Tagetes and they usually tell you it is edible. However, when you ask the internet "Are marigolds edible?" (link), Google has an insert about eating calendulas. Calendulas and marigolds are all mixed up in the popular literature because both have been called marigolds.

Fortunately for us, the commonly cultivated marigold species can be substituted for calendulas. But in the interest of accuracy, I reiterate that the literature on edible flowers is almost entirely about calendulas not marigolds.

marigolds, Granada, Spain
marigolds, Granada, Spain
This confusion extends widely. In India and many other places, calendulas were used for centuries before marigolds arrived from the Americas. Now you see lavish displays of marigolds in India, playing the same roles, with people writing as if no substitution had occurred. Many websites garble the story. Some of easily-accessed websites about marigolds write "marigolds, Calendula officialis" and then show a photo of a marigold, Tagetes (link, link2, link3 )  Other sites attribute calendula folklore to marigolds (Examples: neither the ancient Welsh nor Macer (medieval Germany) knew marigolds, only calendulas; linklink2). These mixed up details probably only matter to a purist like me. However, the website chaos is certainly a reminder that we can and do stick the same common name on any number of different plants (earlier post), which predictably confuses someone.

marigolds, Shanghai, China
marigolds, Shanghai, China
Marigolds are grown all over the world. They came from the Americas after 1492, replacing calendulas in culture after culture, from China to India to Europe to the United States.

marigolds. Lijiang, Yunnan, China
marigolds. Lijiang, Yunnan, China

In upcoming posts: the curious stories I found while trying to untangle calendulas and marigolds.

Comments and corrections welcome.

Foster, S. and R. L. Johnson. 2006. National Geographic Desk Reference to Nature's Medicines. National Geographic Society, Washington, D. C.
All the books listed above, especially
Haughton, C. S. 1978. Green Immigrants. The Plants that Transformed America. 
Martin, L.C. 1987. Garden Flower Folklore. The Globe Pequot Press, Chester Connecticut. 
Thanks to Vladivosta on the Garden Web forum for the link to Lin's Edible Plant books

Marigolds in the Literature Here's what I found looking for marigolds in my collection of plant books
>Edible, An Illustrated Guide to the World's Food Plants. National Geographic. 2008. Pot marigold Calendula officinalis as edible plant. No mention of Tagetes.
>Medicinal Plants in Folk Tradition. An Ethnobotany of Britain and Ireland. David E. Allen and Gabrielle Hatfield. 2004. Uses name marigold for Calendula officinalis, talks of corn marigold and wild marigolds, other native British plants. No mention of Tagetes.
>Edible Flowers. From Garden to Palate. Cathy Wilkinson Barash. 1995. Entries for calendula (Calendula officinalis, name pot marigold noted) and signet marigold (Tagetes tenuifolia) as edible flowers.
>Oxford Book of Plant Lore, (1995) gives you calendula when you look up marigold, Tagetes is in the A's under African marigold. Marigold (calendula) is described as used in tea, African marigold as a companion plant only.
>Salad Lover's Garden. Sam Bittman. 1992. Lists marigolds and calendulas separately as edible flowers. No scientific names given.
>The Miniature Book of Flowers as Food, Jane Newdick and Mary Lawrence. 1991  Recipes for marigold cauliflower, marigold fillets and marigold cake. No scientific names but the pictures make it clear the flowers are calendulas.
>Simon & Schuster's Guide to Herbs and Spices. Gualtiero Simonetti. 1990. Calendula officinalis, calendula, pot marigold entry, no mention of Tagetes
>Rodale's Illustrated Encyclopedia of Herbs. 1987. Calendulas, called pot marigold, as edible. Tagetes included as dye plant. 
>Garden Flower Folklore. Laura C. Martin. 1987. Separate and detailed entries for marigolds and calendulas. States both are edible.
>The Master Book of Herbalism. Paul Beyerl. 1984. No scientific names. Plant is called marigold.  He quotes Gerard, for whom a marigold was Calendula though it is impossible to be sure which plant is intended.
>Annuals and Biennials. Kenneth A. Beckett. 1984. Calendula called marigold, Tagetes called African marigold, French marigold.
>The MacMillan Book of Natural Herb Gardening. Marie-Luise Kreuter. (original 1983), English translation 1985. Pot marigold (Calendula). No mention of Tagetes.
>Health, Happiness and the Pursuit of Herbs. Adele G. Dawson.1980. Calendula or marigold, Calendula officinalis. No mention of Tagetes.
>Green Immigrants. The Plants that Transformed America. Claire Shaver Haughton. 1978. Tells of calendula as the original marigold, with American marigolds coming in after the discovery of America. 
>Who Named the Daisy? Who Named the Rose? Mary Durant. 1976. Marigold entry is about Tagetes, mentions Calendula, says nothing about eating either one. 
>Simon & Schuster's Complete Guide to Plants & Flowers. 1974. Pot marigold (Calenula) is described as edible, French marigold (Tagetes erecta) and African marigold (T. patula) just described as garden annuals. 
>The Concise Herbal Encyclopedia. David Law. 1973. Marigold is Calendula, no mention of Tagetes.
>Herbs & Things. Jeanne Rose's Herbal. 1972. Marigold section specifies Calendula officinalis. There is a mention of French marigold in the "Language of Flowers Section" no scientific name.
>Herbs for Use and for Delight. Daniel J. Foley, editor. 1971. A collection of articles, there are three articles on Calendula officinalis, as marigold and pot marigold, none that talk about the African marigold, French marigold or Tagetes. I checked several of the tables of herbs, as in "herbs grown in the garden on Long Island" and found marigolds (Calendula) no Tagetes.
>Spices and Herbs. Lore and Cookery. Elizabeth S. Hayes. 1961. Pot marigold, CalendulaTagetes does not appear anywhere.
>Growing and Using Herbs and Spices. Milo Miloradovich. 1950. Marigold or Pot Marigold is an entry, given as Calendula officinalis. The genus Tagetes appears nowhere in the book.
1930s (much reprinted classics)
>Herbal Delights. Mrs. C.F. Leyel. 1938 (much reprinted). Marigold is Calendula officinalis, no mention of Tagetes, French marigold or African marigold.
>Old-Time Herbs for Northern Gardens. Minnie Watson Kamm. 1938. Five pages on pot marigold (Calendula)--the entry in the index is just "marigold." Tagetes nowhere mentioned.
>Gardening with Herbs for Flavor and Fragrance. Helen Morgenthau Fox. 1933. Marigold is pot marigold Caledula officinalisTagetes does not appear.
>A Modern Herbal. Mrs. M. Grieve. 1931. Marigold is pot marigold, Calendula officinalis. She notes marsh marigold (Caltha) but there is no mention of Tagetes. Online 

Kathy Keeler, A Wandering Botanist


  1. Hi Kathleen, here in southern California I grow Tagetes lucida, which people call "Mexican tarragon." It's a perennial in my zone like Artemisia dracunculus, but it grows better in my garden than A. dracunculus. I can attest that it's edible! Of course, one person’s testimony shouldn’t elicit a taste test! I think there are a few species of Tagetes that are commonly eaten in Mexico and South America. Since Tagetes originated from there, collective knowledge on which species are edible is more developed. I'm still catching up. Thanks for all the info. Always wondered why Calendula was called "pot marigold."

  2. I put much of what I learned about Tagetes in a separate post because I had too much information. Tagetes lucida isn't grown as an annual in places where there is winter, unlike the others, so is less well known. I don't have access to much information about the uses of other Tagetes species across Central America and into South America, tho I'm sure there's lots going on.