The Jerusalem artichoke (Helianthus tuberosus), also called sunroot, sunchoke, earth apple, or topinambour, is a species of Sunflower native to eastern North America, and found from eastern Canada and Maine west to North Dakota, and south to northern Florida and Texas. It is also cultivated widely across the temperate zone for its tuber, which is used as a root vegetable.
Native Americans cultivated H. tuberosus as a food source. The tubers persist for years after being planted, so that the species expanded its range from central North America to the eastern and western regions. Early European colonists learned of this, and sent tubers back to Europe, where it became a popular crop and naturalized there. It later gradually fell into obscurity in North America, but attempts to market it commercially have been successful in the late 1900s and early 2000s.
The sunchoke contains about 2% protein, no oil, and little starch. It is rich in the carbohydrate inulin (76%), which is a polymer of the monosaccharide fructose. Tubers stored for any length of time convert their inulin into its component fructose. Jerusalem artichokes have an underlying sweet taste because of the fructose, which is about one and a half times as sweet as sucrose.
It has also been reported as a folk remedy for diabetes. Temperature variances have been shown to affect the amount of inulin the Jerusalem artichoke can produce. When not in tropical regions, it makes less inulin than when it is in a warmer region.
Sunchokes can cause flatulence and, in some cases, gastric pain.
Jerusalem artichokes are easy to cultivate, which tempts gardeners to simply leave them completely alone to grow. The quality of the edible tubers degrades, however, unless the plants are dug up and replanted in fertile soil. Because even a small piece of tuber will grow if left in the ground, the plant can ruin gardens by smothering or overshadowing nearby plants and can take over huge areas. Farmers growing Jerusalem artichokes who then rotate the crop may have to treat the field with a weedkiller (such as glyphosate) to stop their spread. Each root can make an additional 75 to 200 tubers during a year.