Asiatic tree of the genus Pogostemon, the leaves of which yield a fragrant oil (9)
I believe the answer is:
patchouli
(Other definitions for patchouli that I've seen before include "Aromatic oil" , "County (abbrev.); weapons" , "scented oil" , "Perfume from the oil of an East Asian shrub - a lit pouch (anag)" , "essential oil" .)