According to Wikipedia Turmeric is a flowering plant, Curcuma longa of the ginger family, Zingiberaceae, the roots of which are used in cooking. Plants are gathered each year for their rhizomes, some for propagation in the following season and some for consumption.
The rhizomes are used fresh or boiled in water and dried, after which they are ground into a deep orange-yellow powder commonly used as a coloring and flavoring agent in many Asian cuisines, especially for curries, as well as for dyeing, characteristics imparted by the principal turmeric constituent, curcumin.
We’ve been planting them for a few years now. They grow pretty much without a lot of care and fertilizer. Growing them seems easier than digging them out to me.