[Rune Son of Bjarne]

If I remember correctly it was Kingsfoil (Athelas) he used, the same thing he used to bath Frodos wound. He state quite clearly that it was a plant brought from Numenor and that the Rangers was some of the only one that still knew about its healing powers. So it is not an elven tradition, they might know it as well, but I doubt that they are more skillful with it than Aragorn.

I suspect that Aragorn would have been the one that could get most out of this plant at all. It has a connection Numenor, called Kingsfoil and there is the old saying about healing from the hands of the king.