"mountain ash," 1804, from rowan-tree, rountree (1540s), northern English and Scottish, from a Scandinavian source (compare Old Norse reynir, Swedish Ronn "the rowan"), ultimately from PIE root *reudh- "red, ruddy," in reference to the berries.
There were those in this neighbourhood, long after the beginning of the present century, who believed that a slip of rowan tree carried on their person dispelled glamour, and rendered nugatory all the powers of sorcery and witchcraft. [Alexander Laing, "Lindores Abbey and the Burgh of Newburgh," Edinburgh, 1876]
