Tip of the Week: Marigolds Have Many Virtues

Posted in Gardening Tips on August 10 2009, by Sonia Uyterhoeven

Sonia Uyterhoeven is Gardener for Public Education. Join her each weekend for home gardening demonstrations on a variety of topics in the Home Gardening Center.

There is a magic to marigolds. They are ubiquitous—you can find them in any garden center and voilá, instant color in the vegetable garden that will last all summer long. 

The power of marigolds extend far beyond their color. Companion planting gurus extol the virtues of marigolds, claiming that they deter aphids, thrips, whiteflies, Mexican bean beetles, squash bugs, and tomato hornworms. With this kind of a reputation, what respectable vegetable gardener would go without them? 

Some marigolds are supposed to deter nematodes that can attack tomato plants. This particular type of nematode tends to strike in sandy soils and is more prevalent in California, Florida, and the Gulf Coast region. If you see a marigold named ‘Nema-gone’ you know what it is advertising. Apparently, ‘Jolly Jester’ works, too.

The common name “marigold” applies to two genera: Tagetes and Calendula. The former (Tagetes) is the marigold that we are all familiar with. These marigolds are indigenous to the southwestern United States, Mexico, and into Central and South America and are generally broken down into four or five types.

Tagetes erecta are the tall marigolds that are commonly referred to as either the African or American marigolds. Tagetes patula, while being native to Central and South America, were predominately hybridized in France and are therefore known as French marigolds. They range in size from dwarf cultivars 5-10 inches tall to larger varieties that reach 12-18 inches tall. When you think of a stinky yet floriferous marigold, this is the one you are picturing.

Hybrids of these two marigolds are starting to flood the market. The sterile hybrids are sometimes referred to as ‘Mule marigolds’, triploid cultivars, hybrids, or ‘New World marigolds’. They combine the best of both parents, producing robust flowers on 12- to 18-inch plants. The catch is that they are not as easy to grow as their parents.

Since we are celebrating The Edible Garden this year, I would like to focus on two lesser known cousins that are edible. Tagetes tenuifolia (syn. signata) is called the signet marigold. Unlike it’s oddly odiferous cousins, this one has an appealing fragrance. Its fine, feathery foliage has a lovely lemony fragrance. The flowers of the signet marigold are edible and can be tossed into a salad or mixed into a dessert sauce.

Tagetes lucida is commonly known as either the Mexican mint marigold or Spanish tarragon. As the common names suggest, it has a sweet licorice flavor that is reminiscent of tarragon. The flowers are used in salads and teas and the leaves are used as a substitute for tarragon, particularly in warm climates where French tarragon will not grow. Careful, though, in large quantities it can cause you too hallucinate.

Calendula or the pot marigold finds its origins in the Mediterranean region. Its Latin name harkens back to the word for calendar. It was given this name because it flowers throughout the calendar year in its native climate and was used in monasteries to decorate alters.

While it does not boast the same pest-repellant properties as its namesake, the pot marigold possesses some wonderful medicinal properties. It is used in ointments to repair damaged skin, the sap from the plant is said to remove calluses and warts, and it has anti-inflammatory and antiseptic properties.

It is also one of the tastiest edible flowers around—at least one of my favorites. You will often find the thin, orange ray petals strewn in some high-end salad mixes. They add a spicy flavor. They are also used in vinegars mixed with dill or thyme and added to herbal butters for good color.

Calendula was given its common name pot marigold because it was often used as a seasoning substitute—a poor man’s version of saffron—and tossed into a pot of rice, soup, or stew.

Why the name marigold? There is a town in California named Marigold, and the British also use the name marigold for the bright-yellow rubber gloves they use to wash their dishes. But the name of the flower has a holier origin: It was named after the Virgin Mary (Mary’s Gold).