Gathering mob's loss, produces flowers (8)
I believe the answer is:
blossoms
'flowers' is the definition.
('blossom' can be a synonym of 'flower')
'gathering mob's loss' is the wordplay.
'gathering' is an anagram indicator (letters gathered in a new way).
'mobs'+'loss'='mobsloss'
'mobsloss' with letters rearranged gives 'BLOSSOMS'.
'produces' acts as a link.
(Other definitions for blossoms that I've seen before include "Develops nicely like flowers" , "Flowers, especially of fruit trees" , "Puts forth flowers" , "Flourishes like flowers from fruit tree (8)" , "Blooms" .)