Shrub generally known not to be hardy (6)
I believe the answer is:
laurel
This clue is a double definition.
'shrub' is the first definition.
(I've seen this before)
'generally known not to be hardy' is the second definition.
(I've seen this before)
(Other definitions for laurel that I've seen before include "Stan possibly" , "Hardy's comic pal" , "Leaf of the wreath of honour" , "Companion to Hardy" , "Hardy's partner - symbol of victory" .)