Two sides bordering study covered in pleasant flowering plant (6,3)
I believe the answer is:
golden rod
'flowering plant' is the definition.
'two sides bordering study covered in pleasant' is the wordplay.
'two sides' becomes 'lr' (abbreviations for left and right).
'bordering' means one lot of letters goes inside another.
'study' becomes 'den' (term for a study or office).
'covered in' means one lot of letters goes inside another.
'pleasant' becomes 'good'.
'lr' going around 'den' is 'ldenr'.
'ldenr' put into 'good' is 'GOLDEN-ROD'.
(Other definitions for golden rod that I've seen before include "Bloomer" , "garden plant" .)