Call back to bring in shrub (5)
I believe the answer is:
lilac
'shrub' is the definition.
(lilac is a kind of shrub)
'call back to bring in' is the wordplay.
'back' shows that the letters should be reversed in order.
'to bring' becomes 'i' (I am not sure about this - if you are sure you should believe this answer much more).
'in' is an insertion indicator.
'call' back-to-front is 'llac'.
'llac' enclosing 'i' is 'LILAC'.
Can you help me to learn more?
(Other definitions for lilac that I've seen before include "Plant" , "Tree with purple or white flowers" , "Tree - pinkish-purple colour" , "Light purple - flowering tree" , "Syringa vulgaris, light purple in colour" .)