Essentially, the difference between a spice and an herb comes down to what part of the plant the ingredient was sourced from. Herbs are typically green, coming from the leaves, flowers, or stems of a plant. Technically speaking, herbs are non-woody plants that typically die off each winter (though some can be overwintered in optimal climates). Spices, on the other hand, can come from many parts of a plant—roots, seeds, fruiting bodies, bark, sap, rhizomes, and other plant parts.