Quebec street (3)
I believe the answer is:
'quebec street' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for rue that I've seen before include "Repentant sort of shrub?" , "Be regretful" , "Regret or repent" , "Bitterly regret - plant" , "The 'herb of grace'" .)