Cardoon (Cynara cardunculus) is a striking vegetable grown for its edible leaf stalks, or petioles, rather than its flower buds. A close relative of the globe artichoke, it shares similar thistle-like foliage and an architectural presence. Native to the Mediterranean, cardoon is cultivated primarily for the flavor and texture of its celery-like stalks.
Site Selection and Sowing
Cardoons require considerable space and perform best in a site that receives full sun, meaning six to eight hours of direct sunlight daily. The plant is a heavy feeder, so the soil should be rich, fertile, and well-draining to prevent root issues. Incorporating compost or well-rotted manure into the bed before planting ensures the necessary nutrient supply for the growing season. Mature cardoon plants need to be spaced generously, ideally three to four feet apart, to allow for proper air circulation and development.
To achieve a long enough growing season, start seeds indoors four to six weeks before the last expected frost date. Seeds should be sown about a quarter-inch deep in individual containers and kept consistently moist at 70 to 80 degrees Fahrenheit for optimal germination. Once the danger of frost has passed, the young plants must be hardened off and transplanted carefully into the prepared garden bed.
Routine Care for Healthy Growth
Cardoons require deep, consistent watering, especially during dry periods, to maintain ample moisture and encourage the development of their large leaf structure. While the plants are somewhat drought-tolerant, providing at least an inch of water per week is best for producing the highest quality edible stems.
As vigorous growers, cardoons benefit from supplemental feeding throughout the summer months because they quickly deplete the soil’s nutrients. Applying a balanced granular fertilizer or side-dressing the plants with aged compost mid-season supports lush, leafy growth. Regular monitoring for common garden pests, such as aphids and slugs, is advised, though cardoon exhibits good resistance to serious disease problems.
Preparing the Stalks for Harvest
Blanching is a unique preparation necessary to ready the stalks for consumption. It involves excluding light from the leaf stalks for a period, which reduces the plant’s natural bitterness and tenderizes the tissues. This process also causes the stalks to lighten in color, moving from green to a desirable pale yellow or white. Blanching should begin in the late summer or early fall, typically three to four weeks before the intended harvest date.
To begin, gather the leaf stalks together loosely, taking care to avoid any sharp or prickly parts of the plant. The stalks are then tied upright with twine or soft material. The entire bundle is wrapped tightly with an opaque material to block out all light. Common wrapping materials include burlap, straw, thick layers of newspaper, or black plastic sheeting. It is important to ensure the very center of the plant remains open at the top to allow for air circulation and prevent moisture buildup, which could lead to rot.
Harvesting and Post-Harvest Handling
After the three to four-week blanching period, the stalks are ready for harvest, usually occurring in the late fall or before a hard frost. To harvest, the entire plant can be cut at ground level using a sharp knife, keeping the blanched stalks intact as a single clump. Alternatively, remove individual outer blanched stalks, leaving the rest of the plant to continue growing. Once harvested, remove the wrapping material and trim the leafy tops away from the edible stem portions.
Before cooking, the tough, stringy outer fibers of the stalks should be peeled away, similar to preparing celery, to improve the texture. This step is especially important for non-spineless varieties, which tend to have more pronounced fibers. Cardoon stalks keep well and can be stored in the refrigerator for one to two weeks if wrapped loosely in plastic or paper. The cleaned stalks are often prepared by boiling them in acidulated water before being used in gratins, stews, or other traditional dishes.