The sunchoke (Helianthus tuberosus) is a perennial sunflower species cultivated for its edible underground tubers. This vegetable is also commonly referred to as the Jerusalem Artichoke, though it is neither an artichoke nor from Jerusalem. Native to North America, it was historically cultivated by indigenous peoples. Successful cultivation involves understanding its growth habit and managing its natural tendency to spread aggressively, ensuring a steady, high-quality harvest. This guide details how to grow this unique vegetable while keeping its vigorous growth contained.
Selecting the Site and Preparing the Soil
Sunchokes thrive best when planted in a location that receives full sun exposure, although they can tolerate partial shade. Choosing the right site is the first defense against their aggressive spreading habit, which occurs through underground rhizomes. These plants are adaptable and will grow in most soil types, but they produce the largest, smoothest tubers in loose, well-draining soil. Heavy clay or waterlogged areas should be avoided, as excessive moisture can cause the tubers to rot. Amending the planting area with well-rotted compost or aged manure improves soil structure and provides necessary nutrients.
Because any small piece of tuber left in the ground can sprout a new plant, it is recommended to plant sunchokes in a dedicated, isolated bed or a large container. A physical barrier is the most effective way to prevent the patch from migrating. Install a root barrier made of metal flashing or heavy-duty plastic, sunk at least 18 inches deep, around the perimeter. Alternatively, using a raised bed lined with hardware cloth or a large container will permanently contain the root system and simplify management.
Planting the Tubers and Initial Care
The optimal time to plant sunchoke tubers is in early spring, once the threat of the last hard frost has passed and the soil is workable. Tubers are planted much like potatoes, needing to be placed at a depth of three to five inches below the soil surface. Select firm, unblemished tubers for planting, ensuring each piece has at least two to three growth buds, or “eyes.”
Proper spacing encourages better air circulation and allows for adequate tuber development, maximizing yield. Tubers should be spaced about 18 to 24 inches apart in rows that are three feet apart. Once covered with soil, they require a thorough initial watering to settle the earth and initiate the growth process. After planting, monitor the area for the emergence of green sprouts, which should appear within a few weeks. While the plants are relatively drought-tolerant once established, providing consistent moisture during the early growth period helps them develop strong root systems. Applying a layer of organic mulch, such as straw or shredded leaves, helps suppress weeds and maintain an even soil temperature and moisture level.
Managing Aggressive Growth and Maintenance
Sunchokes often reach between six and ten feet, meaning they may require support in windy environments. Providing a sturdy stake or a trellis system prevents the tall, thick stalks from snapping under the weight of the developing foliage. These plants are robust, but heavy summer storms can still cause damage to unprotected stems.
The vigorous, spreading nature requires a proactive approach to prevent them from becoming weedy. Regularly patrol the perimeter and immediately cut back any runners or shoots that emerge outside of the intended boundary. This consistent removal of outlying growth maintains the integrity of your containment method. Later in the season, once the plants reach about five to six feet tall, “top” them by cutting off the upper foot of the stem and any developing flower buds. This pruning redirects the plant’s energy away from height and flower production, focusing it instead on underground tuber enlargement. Providing supplemental water during periods of prolonged dryness supports the swelling of the tubers, particularly in late summer and early fall.
Harvesting the Tubers and Storage
The best time to harvest sunchoke tubers is in late fall or early winter, after the first one or two hard frosts have caused the plant’s foliage to die back completely. This exposure to cold converts the inulin stored in the tubers into fructose, which significantly improves their flavor and sweetness. To begin the harvest, cut the dead stalks down to about six inches above the soil line, leaving them as markers.
Use a garden fork to gently loosen the soil starting about a foot away from the remaining stub of the stalk, carefully working inward to avoid spearing the tubers. Lift the entire root ball and brush off the loose soil to reveal the knobby tubers attached to the rhizomes. Ensure that you thoroughly search the surrounding soil and remove all pieces of the tuber, as any fragments left behind will sprout new plants the following spring.
Sunchokes have thin skin and do not store well once removed from the ground, drying out and shriveling quickly. The most effective storage method is to leave the bulk of the crop in the soil and harvest them only as needed throughout the winter. If you must store them indoors, clean the harvested tubers and place them in a perforated plastic bag or container with slightly damp sand or sawdust. Storing them in the coldest part of your refrigerator will keep them fresh for a few weeks.