Cardoons

Cardoons (Cynara cardunculus) are edible thistles from the sunflower family.

​Eaten the same way as celery, or cooked into stews and soups, cardoons are a maintenance-free perennial. The familiar, grocery store variety of artichoke is a type of cardoon, but there are differences.

Native to the dry climate of Morocco, cardoons are unfazed by drought, making them an easy choice in California and other Mediterranean climates. Also known as artichoke thistles, cardoons produce magnificent pinkish-purple spiked flowers from April through July, but it is the stems that are eaten.

Cardoon flowers (Lusitana) CC BY 2.5

Cardoon description

Wild cardoons are sturdy herbaceous perennials that grow 3 to 5 feet tall, with deeply lobed, greenish-gray leaves that can be spiny, hairy, or downy (a condition called tomentose). The fleshy taproot is very good at finding water. And pollinators love the big, showy flowers!

Mature cardoon plant (Magnus Manske) CC BY-SA 3.0

Cardoon types

Cardoons are grown for two different crops, using different cultivars. The familiar globe artichoke (Cynara cardunculus var. scolymus) is grown for its large edible flower buds. The plant referred to as ‘cardoon’ (C. cardunculus var. altilis) is grown, instead, for its edible leaf stems. Since the wild ancestor to cardoons featured painful spines on those stems, spineless cultivars have been developed. Our domesticated artichokes and cardoons are so closely related that they can cross-pollinate, so they should be grown a fair distance from one another.

How cardoons grow

Cardoons need a long, cool growing season, making them an excellent winter crop in the Bay Area. Seeds are started late fall to mid-winter and they transplant easily. These plants grow slowly, at first, but don’t let them fool you. Cardoons can get quite large, averaging 3 feet in all directions. Plants need full sunlight, moderate amounts of water, and good drainage. Watering regularly improves the flavor of cardoon stems. They are frost sensitive, so some protection may be needed in the form of mounded straw or dry leaves around the base of the plant during winter. The plants often die back to ground level after flowering, but they will come back, year after year, adding structure and color in winter, and a spectacular show in spring and early summer.

Immature cardoon flower (Karelj) CC BY-SA 3.0

Harvesting cardoons

Only the tender, inner stalks are eaten. These are harvested before the plant goes to flower. Much like celery, these stalks are wrapped in fabric, paper, or straw during the 30 days of growth. This etiolation, or bleaching, keeps the stems white and tender. Traditionally, the stalks were buried under a mound of soil as the plant grew, but that just sounds like too much work. The stalks are then peeled and treated with a little lemon juice, to prevent browning. Simmer for 30 minutes or so and add to any number of Moroccan, African, Greek, Italian, or Persian dishes. In addition, cardoon seeds contain a high quality oil, similar to sunflower oil and safflower oil.

Cardoon pests and diseases

Like its close cousin, the artichoke, cardoons are vulnerable to feeding by slugs and snails, and the artichoke plume moth. They are also susceptible to the viral disease artichoke curly dwarf. Other than that, they are relatively indestructible.

An invasive weed

Cardoons are so hardy, and they self-seed so readily, that they are categorized as a Most Invasive Wildland Pest Plant by the Invasive Species Compendium. What this means to you, as a home gardener, is that it is very important that mature flowers are deadheaded before seeds can spread. This will protect the environment and prevent your yard from filling up with pokey thistle plants. Cardoons grow and spread so readily that some researchers are studying them as a source of biofuel and bioplastics materials.

Invasive weed or delicious vegetable, cardoons have been part of the human diet since ancient times, only falling out of public favor over the last 100 years.

As easy as it is to grow, perhaps it is time for a cardoon in your foodscape!