Stop the shoot (4)
I believe the answer is:
stem
This clue is a double definition.
'stop' is the first definition.
(I know this)
'the shoot' is the second definition.
(I've seen this in another clue)
(Other definitions for stem that I've seen before include "Slender upright part, of flower or glass" , "Ski turn and plant stalk" , "Shoot; arrest" , "Stop the flow of, check" , "something growing?" .)