For the distinctively flavored Mediterranean plant, its root, and candies and confections made from the root, North American English speakers use licorice. In Ireland and the U.K., liquorice is preferred. We find both spellings used about evenly in Australian and New Zealand publications. Other than the spelling, there is no difference between the words.
Examples
These are North American publications:
This rosado is a year-round wine, gutsy and savory with an exotic flavor of earthy fruit and a touch of licorice. [New York Times]
We’re amazed by the intense flavours of tiny squab breast glazed in dark and spicy birch syrup with wild cattails and licorice-scented fennel. [Globe and Mail]
Enormous color concentration sports aromas and tastes of long-cooked dark fruit jam laced with hints of bacon, smoke, licorice, spice and tobacco. [Chicago Tribune]
And Irish and U.K. publications use liquorice—for example:
It is highly aromatic, powerful, very savoury woody and bitter, with flavours of herbs and liquorice. [Irish Times]
It must be one of the prettiest towns in England, a grid of half-timbered buildings apparently made of mint cake and liquorice strips . . . [Telegraph]
The orange-flavoured and sugar-free lollipop contains a liquorice root extract known to kill the main cavity-causing bacterium in the mouth. [Scottish Daily Record]