New growth starting by fruit just come out with it (5,4,3,3)
I believe the answer is:
shoot from the hip
'just come out with it' is the definition.
(both can mean to say something without thinking)
'new growth starting by fruit' is the wordplay.
'new growth' becomes 'shoot' (a shoot is new growth from a plant).
'starting by' becomes 'from the' (eg 'from the top', starting from the beginning).
'fruit' becomes 'hip' (the fruit of a rose plant).
'shoot'+'fromthe'+'hip'='SHOOT FROM THE HIP'
(Other definitions for shoot from the hip that I've seen before include "be blunt" , "Hastily communicate" , "to put it bluntly" , "Speak without heed of the consequences" , "Speak bluntly" .)