"The Jerusalem artichoke (Helianthus tuberosus), also called the sunroot or sunchoke or earth apple or topinambur, is a species of sunflower native to the eastern United States, from Maine west to North Dakota, and south to northern Florida and Texas.

It is also cultivated widely across the temperate world for its tuber, which is used as a root vegetable." - from Wikipedia

Where to get Jerusalem Artichoke