It's able to grow wild like an animal (7)
I believe the answer is:
bestial
'like an animal' is the definition.
(I've seen this in another clue)
'it's able to grow wild' is the wordplay.
'to grow wild' indicates an anagram (I've seen 'growing wild' mean this).
'its'+'able'='itsable'
'itsable' with letters rearranged gives 'BESTIAL'.
(Other definitions for bestial that I've seen before include "for animals?" , "Animal-like" , "Brutish or cruel, hardly human" , "Tables I create, being brutal or cruel" , "Savage" .)