Photo by Adobe Stock/L.Bouvier
When it comes to plants that make a statement, few compare with cardoon. A stately ornamental edible topped with an otherworldly looking thistle, cardoon (Cynara cardunculus) is a beauty to behold. It’s a close cousin to the artichoke (C. scolymus), with sprawling, spiky foliage that gives way to a tall, edible stalk topped with a striking, globe-shaped purple flower.
Its violet flower and jagged, silvery foliage earned cardoon the Royal Horticultural Society’s Award of Garden Merit from the U.K. Some would argue that its blossom is better left to the bees, because harvesting the stalk would ruin its beauty. Reaching a regal 5 to 6 feet tall, cardoon makes an excellent gateway to an herb or vegetable garden, or a backdrop for lower-growing grasses and perennials.
Cardoon is so glorious in full bloom that its culinary value can easily be overlooked. Its unusual visual appeal may tempt us to leave it at that, but doing so deprives us of an incredible old-world taste. Though cardoon’s savory flavor remains a curiosity in the U.S., we’re gradually beginning to appreciate what Mediterranean chefs have long known: Beneath its beautiful crown, the straight and narrow cardoon stalk is a prized culinary treat.
A Prickly Past
Cardoons and artichokes are members of the Asteraceae family, and share the same ancient DNA. Both bear the characteristic prickly flower bud, and, like most thistles, are eminently edible. Wild cardoon is the probable progenitor of both species. It originated in the Mediterranean basin, likely in Sicily or North Africa. There’s little documentation regarding the cultivation of cardoon, but we know that it occurred later than the domestication of the globe artichoke.
Pliny the Elder mentioned two types of edible thistles in his writings, commonly believed to be cardoon and artichoke. He heralded the plants’ health benefits, from curing digestive ailments to reversing baldness. We can deduce from his writings and other similar records that early Romans domesticated globe artichokes around the 1st century A.D. They preferred smooth, thick artichoke buds, and selected crops based on those characteristics.
Photo by Baker Creek Heirloom Seeds
Artichokes lost favor in most of Europe around the time of the fall of the Roman Empire. However, Arabs sustained their popularity in a few Mediterranean countries. They also began foraging for wild cardoon flower buds and leafy stalks. Preference for the fibrous, vegetal stalk eventually led to the cultivation of cardoons throughout the Mediterranean, where it remains popular today.
Despite falling in and out of favor throughout history, artichokes and cardoons sustained some loyal followers over the centuries. French immigrants introduced globe artichokes to American colonists in the 18th century. And, for a while, they were one of Thomas Jefferson’s favorite crops. However, early varieties weren’t particularly hardy in his Zone 7 Monticello garden, and, suffice it to say, cardoon didn’t stand much of a chance either.
Unlike the artichoke bud, whose meaty outer leaves and tender heart are sought-after spring delicacies, cardoon never quite caught on in the United States. Deprived of its deeply pinnate foliage and glorious crown, the edible portion of the plant appears rather pedestrian on dinner tables and market stands. Perhaps that’s why American consumers tend to overlook cardoon: We neither recognize it nor know how to prepare it. But that’s changing; a growing interest in wild and ancient foods is bolstering cardoon’s reemergence.
Today’s cardoons thrive as perennials in Zones 7 through 10. They grow best in climates that mimic their Mediterranean origins, with mild winters and hot, dry summers. Unfortunately, the plants are a little too well-adapted to California’s climate, and are now listed as an invasive species throughout the state and parts of the Pacific Northwest.
Cardoons also grow well as annuals in cooler Zones. A shorter growing season may not allow them time to bloom, but gardeners in northern regions need not feel discouraged: Harvesting cardoon before the flower matures produces tenderer stalks.
Cardoon plants need space to grow, as well as full sun and rich soil. In regions with colder winters, it’s best to start cardoon seeds indoors 6 to 8 weeks before your final frost date. Around that same time, prepare a garden bed to ensure well-draining soil and a pH of 6.0 to 7.0. Compost may be necessary, as well as humus-rich soil amendments.
Photo by Baker Creek Heirloom Seeds
Begin hardening off the seedlings 3 to 4 weeks after your final frost date by setting them outdoors for several hours at a time each day. Increase the duration of outdoor time gradually, over the course of one week. Transplant the seedlings on a warm, overcast day, spacing them 3 to 4 feet apart.
Cardoons need good drainage and frequent watering to grow successfully. It’s OK if the plants dry out a little between waterings, but they shouldn’t be deprived of moisture for long. As the leaves emerge, some will become heavy and fall under their own weight; remove these leaves so that new ones can sprout. Cardoon’s elaborate foliage adds textural interest to perennial borders and mixed flowerbeds. Leaves at the base of the plant may be removed to encourage a tidy habit and make room for an array of lower-growing companions.
Cardoons grown for edible enjoyment are frequently blanched twice: first in the garden before harvest, and again in the kitchen before cooking. Blanching plants before harvest keeps the stalks tender and preserves their delicate texture and flavor. Cardoons mature about 120 to 150 days after planting, and blanching should occur 4 to 6 weeks before harvest. Begin the blanching process in late summer, toward the end of the growing season. A common approach is to bundle cardoon leaves together and wrap burlap from the base to the middle of the stalk. Blanching can also be achieved by layering hay around the base, and then mounding soil around to create an 18-inch hill. Balancing untreated slabs of wood against the stalk is also effective.
Once the stalks are blanched, cut them off close to the ground. After harvest, perennial plants can be induced to overwinter with a light mulch or loosely tented row cover.
Cardoon in the Kitchen
Cardoon’s flavor is reminiscent of celery and artichoke heart. Once you’re familiar with the plant, it proves no more difficult to prepare than artichoke. Plus, cardoon is a low-calorie food, and is rich in folates, minerals, and antioxidants.
Cardoon skin is tough and, depending on the cultivar, can be very prickly. For this reason, you may prefer to wear gloves while working with the stalks. First, remove the top part of the plant, leaving the bottom 18 to 24 inches for use, and strip away any remaining leaves. Next, use a vegetable peeler to remove the rigid outer skin. When pared down and prepped for cooking, cardoons resemble giant celery stalks.
Like peeled artichokes, cardoon flesh turns brown when exposed to air. To prevent oxidation, place the peeled stalks in a bowl of water with lemon juice or vinegar while awaiting further preparation. From there, the process is only as difficult you want it to be.
Photo by Getty Images/seven75
Depending on how they’ll be cooked, many recipes require you to blanch cardoon stalks. Ancient Greeks and Romans simply cured the peeled stalks in vinegar and honey. Over the centuries, Italians perfected and broadened preparations of their beloved cardi. Mature stalks are braised alongside any variety of root vegetables, legumes, and slow-cooked meats; they’re also commonly drenched in bechamel sauce, stewed for cardi al forno, or coated in cheese and breadcrumbs.
For a simple preparation, cut the stalks into 6-inch slices and steam them for 30 minutes, or until tender. (Young, slender stalks will cook more quickly than mature stalks.) Serve the slices with bagna cauda sauce, or add them to crudités platters for a savory appetizer or snack.
Cardoons ripen between November and February in southern Europe, and are a cherished part of winter holiday meals. They’re a key ingredient in one of Spain’s traditional dishes, cocido madrileno, a stew made from meat and seasonal vegetables. And in French-influenced New Orleans, natives know to stock up on cardoons in March, in anticipation of St. Joseph’s Day; carduni fritti — battered and fried cardoon stalks — are part of the holiday feast.
As if the plant isn’t curious enough, another quirky characteristic is that the pistils found in cardoon flowers produce a vegetarian form of rennet. So it should be no surprise that cheese is a natural companion to cardoon. In Spain and Portugal, cardoon flower rennet has been used for centuries to make sheep and goat’s milk cheeses.
A Gardener’s Dream
Given the right space, cardoon deserves a spot in the garden. How often do we get to stretch the far reaches of our garden’s potential, while exercising our culinary curiosity? And if the flavor doesn’t suit your taste buds, the flower bud is guaranteed to draw a range of garden visitors, from curious passersby to migrating pollinators. What more can a gardener wish for?
Brenda Lynn Kouyoumdjian is a freelance writer, Master Gardener, and beekeeper in northern Virginia.