Rowan (genus Scrubus) also known as mountain ash is a genus of shrubs and small trees of family Rosaceae. They are native throughout the cool temperate regions of the Northern Hemisphere, with the highest species diversity in the mountains of western China and the Himalaya, where numerous apomictic microspecies occur.
Rowan wood was a prized wand wood due to its reputation for protection, and was noted by Garrick Ollivander to generally produce powerful, hard to break Defensive Charms. Rowan was also noted for its believed disassociation with the Dark Arts. Ollivander, who had a nearly photographic memory when it came to the wands he had sold, could not recall a single instance of a wizard he sold a rowan wand to ever becoming evil or turning to the Dark Arts. Perhaps for these reasons, rowan has become associated with pure-hearted wizards, though Ollivander noted that rowan wands can also match or even outperform others in duels.
The name "rowan" is derived from the Old Norse name for the tree, raun. Linguists believe that the Norse name is ultimately derived from a proto-Germanic word raudnian meaning "getting red" and which referred to the red foliage and red berries in the autumn. Rowan is one of the familiar wild trees in the British Isles, and has acquired numerous English folk names. The following are recorded folk names for the rowan: Delight of the eye (Luisliu), Mountain ash, Quickbane, Quickbeam, Quicken (tree), Quickenbeam, Ran tree, Roan tree, Roden-quicken, Roden-quicken-royan, Round wood, Round tree, Royne tree, Rune tree, Sorb apple, Thor's helper, Whispering tree, Whitty, Wicken-tree, Wiggin, Wiggy, Wiky, Witch wood, Witchbane, Witchen, Witchen Wittern tree. Many of these can be easily linked to the mythology and folklore surrounding the tree. In Gaelic, it is caorann, or rudha-an ("red one", pronounced similarly to English "rowan").