Shrublands have suffered, primarily after hot weather (6)
I believe the answer is:
heaths
'shrublands' is the definition.
(I've seen this in another clue)
'have suffered primarily after hot weather' is the wordplay.
'primarily' indicates taking the first letters.
'after' is a charade indicator (letters next to each other).
'hot weather' becomes 'heat'.
The initial letters of 'have suffered' is 'hs'.
'hs' after 'heat' is 'HEATHS'.
(Other definitions for heaths that I've seen before include "Moors" , "Sandy areas; shrubs" , "Moorlands" , "Tracts of wasteland with scrubby vegetation" .)