We know that Holly and Phoenix Tail Feather is a more powerful combination than when paired with Unicorn Hair or Dragon Heartstring.
Holly is one of those woods that varies most dramatically in performance depending on the wand core, and it is a notoriously difficult wood to team with phoenix feather, as the wood's volatility conflicts strangely with the phoenix's detachment. In the unusual event of such a pairing finding its ideal match, however, nothing and nobody should stand in their way.
Why is this so? Are some wand wood more "reactive" to some core and produce stronger magic?