Also called sunroot, sunchoke, wild sunflower, topinambur, or earth apple. Jerusalem artichoke is a species of sunflower native to central North America. A hardy and tennacious plant that comes back each year from tubers that overwinter in the ground. 
 
Sunchokes have massive food producing potential and offer crucial calories during the "hungry gap" time of year, from late winter to early spring.
 
Survival gardeners can rely on sunchokes to thrive even in droughty and adverse conditions. The tubers can be "stored" in the ground and dug when needed anytime throughout the winter.
 
Take note, however, that you should plant tubers they can be allowed to stay permanently, since they are not easily removed from the garden. Even small tuber pieces will resprout to form a thick cluster of sunchokes in future years.
 
Tubers will ship ready to be planted or you can temporarily store them in barely-damp peat moss in a refrigerator. Tubers for seed range in size from 1/2" to 2".