Plant life for all, almost entirely destroyed (5)
I believe the answer is:
flora
'plant life' is the definition.
(I've seen this before)
'for all almost entirely destroyed' is the wordplay.
'almost entirely' means to remove the last letter.
'destroyed' indicates an anagram.
'for'+'all'='forall'
'forall' with its last letter removed is 'foral'.
'foral' with letters rearranged gives 'FLORA'.
(Other definitions for flora that I've seen before include "list of plant life" , "Plants of a particular region" , "For example, Miss Macdonald" , "A region's plants" , "Plants of a region or age" .)