Plant in the shade (5)
I believe the answer is:
lilac
I believe this clue is a double definition.
'plant' is the first definition.
(type of plant)
'the shade' is the second definition.
(lilac is a shade of purple)
'in' acts as a link.
(Other definitions for lilac that I've seen before include "Spiritual knowledge" , "Pinkish purple - shrub" , "Pale violet hue" , "Drop by about one, turning" , "Shrub with fragment purple or white flowers" .)