Artichokes are a ritualistic food that require patience, good conversation, and a nice glass of white wine to be truly appreciated.
Modern artichokes (Cynara cardunculus var. scolymus) have evolved from the cardoon, a plant still grown in Spain and Portugal as a vegetable for its stalks and immature buds, and as a source of plant-based rennet for cheese making. Artichokes found in grocery stores today tend to be larger and tougher than is ideal. Gardeners can enjoy a more tender and flavorful experience by growing these prehistoric-looking members of the sunflower family (Asteraceae) themselves. As a health benefit, artichokes contain more antioxidants than most other vegetables.
Artichoke buds & flowers
The artichokes we eat are actually spiny, immature flower buds. Each artichoke that we buy or harvest is made up of a cluster, or inflorescence, of hundreds of smaller flowers, protected by modified leaves called bracts. Once these flowers bloom, the meaty bracts and the base, or heart, are too tough to eat. The lovely purple flowers are nice to look at, however.
Do you have space for artichokes?
Artichokes can be grown practically anywhere, but they are large plants, averaging 4 to 6 feet across, so be sure to give them room to grow. They prefer cool, moist summers (or relatively shady spots) and mild winters. The majority of the commercial crop is grown in the central, coastal areas of California. While most artichokes are grown as annuals, the plants can actually be grown as perennials, producing edible buds for 4 or 5 years. Under the right conditions, you may be able to harvest as many as 30 artichokes per plant per year. To get the most out of your artichoke plants, it is important to provide light soil (add compost!), water in summer and improve drainage for winter.
Artichokes & temperature
Timing is critical when starting artichokes from seed and when selecting varieties. The heirloom varieties (‘Violetta Precoce’, ‘Green Globe’, or ‘Romanesco’) are very temperature sensitive and will not grow well in northern regions. ‘Opera’ and ‘Imperial Star’ are better choices for colder areas. ‘Green Globe’ and ‘Imperial Star’ perform well in the San Jose, CA area.
Artichoke varieties & propagation
Artichokes are either green or purple. Traditionally, artichokes are a warm weather crop that can be propagated vegetatively or by planting seeds. Varieties that perform better through vegetative propagation include Italy’s large purple Romanesco, Spain’s medium green ‘Blanca de Tudela’, and Peru’s spend ‘Spinoso e Inguano’. Vegetative propagation refers to division and root cuttings.
To divide an artichoke plant, simply wait for new growth to appear in spring. Sink a shovel between the new shoot and the parent plant, lifting the new growth with the shovel and transplanting it elsewhere. Root cuttings can be taken from established plants and placed in a favorable growth medium (moist soil) and allowed to create a new stem and become a complex, independent plant.
How to grow artichokes from seed
Many varieties of artichoke perform well when grown from seed, but it may take a period of vernalization before flowering begins. Green ‘Harmony’ or ‘Symphony’ and purple ‘Opal’, ‘Concerto’ or ‘Tempo’ can all be grown from seed. Since artichokes have deep taproots, they are not well suited to container gardening. Seedlings should be handled very carefully when transplanting. It is easiest to simply plant them in the ground where you want them to give the taproot the freedom to grow deeply, without interruption. Artichoke seeds should be sown 1/4 to 1/2 inch deep at a time when temperatures are expected to be in the 70 - 75º range for a few weeks.
Artichokes are heavy feeders. Using a side dressing (adding fertilizer or aged compost next to plants, where it is watered into the soil around the roots, rather than digging it in), each mature plant will need 1/10 of a pound of nitrogen at the beginning of the growing season. Plants will also benefit from 1 cup of ammonium sulfate and 2/3 cup of ammonium nitrate during the harvest season. If you are like me and prefer a more natural approach, simply keep mulching the area around each plant with aged compost. Blood meal can provide the nitrogen.
Artichoke pests & diseases
Aphids and slugs are an artichoke’s most common pests. At the end of each growing season, many pests can be thwarted by cutting the stems to ground level and covering with mulch. Artichoke plume moths can be a problem in perennial beds. Artichoke curly dwarf is a viral disease that causes stunting and dark, necrotic (dead) spots. To avoid this problem, use only disease-free stock. Botrytis, or grey mold, is a fungal disease that occurs after extended periods of warm, wet weather.
Harvest your artichokes when they are about the size of an apple for the best flavor and tenderness.
A funny side note about artichokes: the fleshy leaves contain a chemical, called cynarine, that inhibits certain taste receptors, making water and other things taste sweeter!
You can grow a surprising amount of food in your own yard. Ask me how!