Jerusalem artichokes (Helianthus tuberosus) is a variety of sunflower native to Eastern North America. However, it has been naturalized and is found in all but five states and also in Canada. It is also called sunroot, sunchoke, earth apple or topinambour. Jerusalem artichokes are herbaceous perennials. They grow to be seven to ten feet tall with four to eight inch long leaves. The leaves are almost opposite each other. The flowers are yellow with yellow centers and look a lot like a daisy. This plant flowers early to mid-autumn. However, the Jerusalem artichoke is grown almost exclusively for its edible root. It its native range (zone three to nine), it is considered a weed. Jerusalem artichokes attract butterflies and birds and tolerate deer. The flowers make nice cut flowers.
Jerusalem artichokes have a spread of three to five feet. They also grow to be seven to ten feet tall. Make sure that where ever you plant these vegetables, they have plenty of room to grow to their full size. They grow best in full sun but will grow in part shade. Plant them where there is shelter from strong winds.
Plant Jerusalem artichokes in fall after the first frost has arrived or in the spring after the last frost of the season. They should be planted three to six inches deep. They need to be planted every two feet to allow them to spread out comfortably. They will grow best in fertile soil with lots of compost mixed in with the soil. However, they can tolerate less fertile soil and will grow in sandy, rocky soil, too. One thing they need is good drainage. They will not tolerate wet feet. After Jerusalem artichokes are established they are relatively drought tolerant. However, it is best to keep the soil around them moist but not soggy. Mulch should be spread around the spring plantings of the Jerusalem artichoke when they are one foot tall. This helps to hold in water and keep out weeds.
Songbirds love the seed heads that form from the flowers. Finches are especially fond of them. If you can, try not to deadhead the plants or cut down the foliage so that the birds can eat the seeds in the winter when food is scarce.
Jerusalem artichokes will spread by rhizomes and self seeding. They can become invasive. They are hard to remove from the garden because if you leave even one small piece of a rhizome, they will grow again.
Tubers are generally harvested two weeks after the flowers fade. Carefully dig up the plant and cut the tubers off the rhizomes. Each plant generally produces two to five pounds of tubers. You usually do not have to replant a Jerusalem artichoke patch because bits of rhizome will remain in the ground and grow back.
These tubers can be eaten raw or cooked. They may be used in all the ways a potato is used. However, tubers do not contain starch.
Jerusalem artichokes are vulnerable to rust, leaf fungal spots and powdery mildew. Caterpillars and beetles often cause damage to the foliage of the plant. Because the plant grows so tall, it may need staking to support the stalk and flowers if it is exposed to the wind.