DIY Network

Cardoon Overview Joe Lamp'l plants cardoon seeds both in a newly prepped garden bed and in pots to use as ornamental specimens in the landscape. From "Fresh from the Garden" episode DFFG-311

Figure A

Also known as artichoke thistle or wild artichoke, cardoon is not well known to many gardeners. A member of the aster family (as is the sunflower), it's a prolific perennial that will come back year after year if the roots are protected from heavy frost. Cardoon looks like a cross between a celery head and an artichoke (figure A). Like celery, the stems are the edible part, although the immature flower heads can be boiled and eaten as well. The plant originated in the Mediterranean region, where it's still very popular with gardeners.

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Cardoon stems, which look like giant spiny celery, taste slightly milder than celery and artichoke as long as they're harvested before temperatures get too hot. The stems and leaves on cardoon plants are so attractive that they're sometimes used as ornamentals rather than as a vegetable crop (figure B).

The flowers of the cardoon plant are intriguing: they start out looking like giant green buds, similar to a globe artichoke only smaller, and then blossom into purple thistles (figure C). The bright colors attract bees and butterflies. As the flower opens, the thistles fly away with the new seeds attached.

Figure B

Figure C

A cardoon plant has its drawbacks: It's beautiful to look at, but in some parts of the country the seeds have spread so rapidly that it's considered a dangerous weed. This is especially true in California, where cardoon has taken over large areas of land. Each seed head can contain 100 to 200 seeds, and if a plant produces a dozen flowers, you can see how many seeds a single plant can release.

Planting Cardoon

1. Once you decide to plant this delicious vegetable, you'll need to find a place with deep, rich soil to grow it. Cardoons can get from 4' to 7' tall, and they have very deep roots. The deeper you dig the soil, the faster the plant will grow. Rich, loamy, well-drained soil is best for cardoons. You want cardoon to grow quickly so you can harvest it before hot weather sets in: any cardoon stem that gets too hot will get more fibrous and bitter.

2. Since cardoon likes rich, deep soil, add several bags of composted manure and soil conditioner to your garden bed (figure D). The manure will provide nitrogen to produce healthy stems and leaves, and the soil conditioner will make the dirt drain more quickly. Soil conditioner also has many of the nutrients that the cardoons will need to flourish. A sprinkling of 10-10-10 fertilizer will also help the cardoon get off to a great start (figure E).

Figure D

Figure E

3. You can order cardoon seeds from a mail-order catalog. Although several varieties of cardoon are grown in Europe, only one kind is usually available in the U. S.; its seeds, called simply "cardoon," have been carefully selected to get the most tender stems possible. Since cardoon can get quite large, 7' tall by 6' wide, don't plant too many seeds in one bed (figure F).

4. Cardoon seeds can be sown directly in the ground, or you can set out seedlings after the first frost. Seedlings will get off to a quicker start, especially if you live in a colder climate where cardoon grows as an annual. If you plant seeds, space them evenly apart in your bed, with the seeds under 1/4" to 1/2" of loose soil (figure G). Seedlings should be planted so that the top of the dirt around the seedling is even with the soil level in the bed.

Figure F

Figure G

5. The seeds should germinate within a few weeks. Early planting of cardoon may mean that you can harvest the stalks before summer. As the plants come up, keep a close eye on them: the bed will get overly crowded very quickly if they all germinate. Also, to get the best flavor, the stems need to be blanched, or protected from the sun, before they get dark green and tough.

6. A layer of straw will protect the cardoon seeds until they get going (figure H). Birds and field mice love these seeds, so the straw will give them added protection. The plants will get mulched all season to the keep soil cooler.

Since cardoon is so versatile as an ornamental, you can plant extra seeds in large pots. Cardoon left to grow on its own will make wide, tall, interesting plants, a real focal point in a landscape (figure I). During the summer the top will have huge, attractive purple blooms that resemble thistles.

Figure H

Figure I

1. To grow cardoon in a pot, plant it just as you would any other container. First line the bottom with weed cloth (figure J) and gravel (figure K), then add potting soil up to a few inches from the top (figure L).

Figure J

Figure K

Figure L

2. Place the seeds just under the soil, in the middle of the pot. You can cover the top of the pot with mulch until the seeds come up (figure M).

3. The pot will have to be watered regularly to keep the soil moist (figure N); otherwise the cardoon may wilt or bend over, and this plant looks best when it stands straight. Cardoon is a very interesting and versatile addition to any garden or landscape.

Figure M

Figure N