The cardoon is a vegetable plant that belongs to the asteraceae family. It’s native to the Mediterranean area.
Key cardoon facts:
Botanical name – Cynara cardunculus ssp. cardunculus
Family – Asteraceae
Type – vegetable
Height – 2 to 6 feet (0.60 to 2 m)
Planting distance – 3 feet (1m)
Exposure – full sun
Soil – rich and cool
Planting – Mid-May
Harvest – from summer to fall
There are two types of cardoon: thorny varieties and thornless ones which only have very few thorns. Today, thornless varieties are the ones most grown and cultivated. Cardoon grows into wide clumps that have large, lobed leaves with fleshy stems that are called stalks. Cardoon tastes very much like artichoke, though it’s a bit more bitter. Take note that cardoon is different from a similar-looking plant: silverbeet. Unlike silverbeet, cardoon leaves aren’t edible. Only the stalks are eaten after blanching.
Seedlings are started in a cold greenhouse, either in a tray or in individual nursery pots, as early as April. It’s also possible to sow directly in the ground mid-May, if the soil has warmed up enough. On average, about 5 months are needed between sowing and harvest.
Sow your cardoon seeds in rich and well drained substrate. After sprouting, thin to only keep the most vigorous ones. If you started your plants in nursery pots, keep just a single plant per pot.
Sow 3 to 4 seeds per seed hole, in soil that’s enriched with ripe compost. Water your seedlings abundantly until they sprout. After each plant has produced three leaves, thin to only keep the nicest seedlings, 1 per 3 feet squared (1 m²).
From the seedling stage, cardoon seedlings are transplanted to the ground when they have about 3 leaves. Do this after the last frost date, which is usually mid-May in most areas. Note that it’s also possible to start sowing and planting seedlings in the previous year, in fall: this helps seedlings spread roots during the winter.
- Plant your cardoon sprouts in holes 8 to 12 inches deep, filled in with soil amended with compost or manure.
- Again, space each planting hole by at least 3 feet (1m) to each side. Once the clump is in place, backfill with soil and ripe compost, press it down, and water.
- The substrate must stay moist without staying drenched though. This maximizes growth.
Growing and caring for cardoon
Cardoon is a vegetable plant that loves it when the soil is always cool. As a result, a key success factor is to mulch the base of each plant with either dried leaves or dried lawn clippings (not fresh ones).
Not a hardy plant, you’ll have to protect your cardoon over winter with a thick layer of natural mulch. Its average hardiness is about 20°F (-7°C). In colder areas, it must be grown as an annual.
Cut the (very ornamental) flower scapes to keep the plant from wasting energy on blooming and seeds, except for a few of the nicest specimens that you select to produce seeds for next year’s crop.
Diseases and pests:
Snails and slugs particularly love young cardoon sprouts. When young, it also attracts black aphids that lodge themselves on its leaves and crown.
Harvest and keeping cardoon
Cardoon stalk harvest takes place between summer and fall, after a 3-week “blanching” period. Harvest each cardoon stalk by cutting them at the base with a knife.
How to blanch cardoon?
Since it takes about 3 weeks for cardoon stalks to turn white, you have to prepare this stem in fall. Anticipate your culinary needs by about 3 weeks, and count how many clumps you need to cover so that they’re ready to harvest three weeks later. Blanching is a step that’s necessary before the harvest: practically speaking, the goal is to keep the leaves and stems in the dark for about 3 weeks to have whiter, softer stems.
- Ridge up the earth to a height of around 8 inches (20 cm).
- Bunch the leaves up back towards the center, and tie them together loosely so that air can still circulate.
- With either a mulching tarp or simple cardboard, wrap each cardoon clump to block light from reaching the lower 3/4ths.
- After 3 to 4 weeks, you’ll notice the stalks wilting somewhat.
Eat quickly after the harvest. Wrapped in a cloth or paper towels, stalks will keep for only a few days at most in the vegetable compartment of your refrigerator. Another option is to pull the entire clump out with its root ball. Store it in the dark for the entire winter if need be.
Cooking with cardoon
The delicate aroma of cardoon stalks pairs well with many recipes. Prepare them by dipping them for a few minutes in salted boiling water with a dash of lemon juice: blanching (that’s the other “blanching”: the cooking one).
Once that’s done, bake them, mash them, or steam them and sauté them in a pan to pair with meats. Also delicious with tomato or bechamel sauce.