When the rest of the garden begins to show signs of senescence with the onset of cold weather, Jerusalem artichoke shines forth. Throughout the warm season, it offers little in return for the space its rampant growth occupies in the garden. Its hairy stalks grow vigorously for months, casting shade upon nearby plants. Beginning in September, however, masses of three-inch yellow flowers bedeck the tops of sturdy, 10-to-12-foot stems. Their sunflower shapes reflect the plant’s botanical lineage as helianthus tuberosus (literal translation: lumpy sunflower).
These bright blossoms are a welcomed sight as frost nips other more delicate petals; however, it is the tubers that we are after. Its name is perplexing for it has nothing to do with Jerusalem nor is it related to the artichoke. “Jerusalem” is most likely a misnomer for “girasol,” the Italian name for sunflower, while the lingering sweetness left on the tongue may resemble the aftertaste of globe artichokes. Perhaps a more accurate name for this late season vegetable is “sunchoke,” which is how chefs commonly refer to it.
A native of this continent, it is a hardy perennial that adapts well to a wide range of soil types. In the fall, one can often spot stands of these golden blooms, growing wild by the roadside and along the edge of abandoned fields. Multiplying readily, new plants sprout from the smallest pieces left in the ground. As such, sunchokes are sometimes considered invasive and should be given ample space or, better yet, planted outside of a fenced in garden. Aside from a few nibbles by voles when the winter ground thaws, few pests or diseases bother this resilient plant. To establish a new bed in the spring, space tubers 12 inches apart and cover with four inches of sandy loam in a sunny spot. The tubers continue to develop throughout the fall, so they should be harvested after hard frost but before the ground is frozen solid. Every year, I intentionally leave behind some small pieces for next year’s harvest, thereby easily creating a self-perpetuating crop. I find that if I rinse and air-dry the tubers directly upon harvest, there is no need to peel them. Older tubers, particularly those missed in previous years’ harvests, tend to be knobby and difficult to clean. To avoid oxidation, immediately submerge peeled or severed sections in water with vinegar or lemon.
When exposed to cold, either in the ground or in storage, the tuber’s carbohydrates convert to fructose, which renders them sweeter. In fact, sunchokes store well for months in a cool, moist environment, such as the refrigerator drawer or packed in moist sand in a root cellar.
Eaten raw, sunchoke has a crispy texture and nutty sweetness that resembles water chestnuts. When cooked, it becomes starchier and is a good alternative to potatoes for diabetics. It may also be dehydrated and ground into flour. In France, the tubers have long been used for wine and beer production. I prefer roasting the tubers after coating them lightly with olive oil, as well as pureeing them in a vegetarian soup made with leeks, garlic, carrots and celery. Rich in iron, potassium and vitamin B, this easy to grow vegetable is a welcomed staple in our winter diet.