Like me, my brother who lives in North Carolina is an avid home gardener. He focuses his green-thumb energies on growing vegetables and is especially proud of his globe artichokes. I am a bit jealous, since artichokes are almost impossible to grow successfully in our region due to our cold winters and hot summers. Artichokes grow best where winter weather is not too frosty and summers are relatively cool and humid.
Artichokes are an interesting vegetable. They are a perennial that is grown for its tasty flower buds. Native to the Mediterranean area, they were grown in Greek and Roman gardens as long ago as the eighth century. Their cultivation spread to Egypt, Spain, Holland, England and other European countries. French and Spanish immigrants brought them to this country in the 19th century.
When I first saw artichokes growing in a California field, I was enthralled with their distinctive appearance. The globe artichoke is a type of thistle and is a member of the aster family (Asteraceae). The coarse-looking plants have fat stems, cone-like flower buds and amazing large, spiny, silvery-green leaves. The edible portion of the artichoke is the fleshy bases of the green scales of immature flower buds.
One reason why we cannot grow artichokes in area gardens is our winter climate. We live in hardiness Zone 6, but most artichokes are only hardy in Zones 7 and above. However, there is one variety, Violetto, that is hardy in Zone 6. Violetto produces smaller elongated, purple-tinged baby artichokes.
Another option in cold regions like ours is to grow artichokes as annual vegetables. One variety, Imperial Star, was bred specifically for production as an annual and is probably the best option for gardeners in colder areas. Each plant produces about 6 to 8 artichokes on 3- to 4-foot-tall plants. Tempo is another variety that can be treated as an annual since it produces from seed its first season. One catch is that these varieties both require a long growing season of 85 to 100 days in length.
Our hot summer climate is the other major stumbling block in growing ’chokes here. If it gets too hot, the plants go into a summer dormancy and do not produce any flowers. Keeping the soil moderately moist and applying a heavy mulch may help a little. A University of California publication suggests that shading and misting to cool the plants may help too, but says it is likely any buds that are produced will be very tough.
If those two obstacles weren’t enough, it is difficult to start artichokes from seed. The seed must be planted 2 to 3 months before planting outdoors in early spring. They require a cool treatment, called vernalization, to induce the formation of the flower stalk and buds. To accomplish this, seedlings must be set out early enough to be exposed to 8 to 10 days of cool temperatures below 50 degrees but above freezing.
Artichokes are a lot of work to grow in our region with only the slightest possibility of harvesting any edible buds. I guess I will just have to get my artichokes at the grocery store. That is OK; I am happy with the many warm season veggies, like tomatoes, that do grow well here.
Marianne C. Ophardt is a retired horticulturist for Washington State University Benton County Extension.