Plant in midst of minor blaze (7)
I believe the answer is:
inferno
'blaze' is the definition.
(I've seen this before)
'plant in midst of minor' is the wordplay.
'plant' becomes 'fern' (fern is a kind of plant).
'in' indicates putting letters inside.
'midst of' means to look at the middle letters.
The middle letters of 'minor' are 'ino'.
'fern' put inside 'ino' is 'INFERNO'.
(Other definitions for inferno that I've seen before include "Dante's scene of horror" , "blazer?" , "A raging fire as in hell - ask Dante" , "Great fire" , "Huge conflagration" .)