Feed dung, spread by back of bush — its growth could prove fruitful (5,4)
I believe the answer is:
hedge fund
'its growth could prove fruitful' is the definition.
(a hedge fund grows financially)
'feed dung spread by back of bush' is the wordplay.
'spread' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'back of' suggests the final letters.
The final letter of 'bush' is 'h'.
'feed'+'dung'='feeddung'
'feeddung' anagrammed gives 'edgefund'.
'edgefund' put after 'h' is 'HEDGE FUND'.
(Another definition for hedge fund that I've seen is " Investment company using high-risk techniques - he fed dung (anag)".)