Harry Potter's wand is made of holly with a phoenix feather core. It is 11 inches long and supple. Interestingly, it is one of only two wands that Fawkes the phoenix lent feathers to for their cores. The other wand, made of yew, belonged to Tom Riddle, a.k.a Lord Voldemort.
In ancient Ireland, the Druids believed that the holly protected against evil spirits and dark magic. Cutting down an entire tree was bad luck, but cuttings could be taken for decoration, rituals and supposedly, magic wands. Some believe that Jesus' crown of thorns was made from holly wood.
The phoenix is a mythical bird, native to Arabia, who burns itself every 500 years, only to be reborn from the ashes. In the Harry Potter universe, its song and tears have amazing healing powers.