Spades needed after salad plant shoots up (7)
I believe the answer is:
rockets
'shoots up' is the definition.
'spades needed after salad plant' is the wordplay.
'spades' becomes 's' (abbreviation in card games).
'needed after' is a charade indicator (letters next to each other).
'salad plant' becomes 'rocket' (I've seen this before).
's' put after 'rocket' is 'ROCKETS'.
(Other definitions for rockets that I've seen before include "moves fast" , "Shoots up abruptly" , "Their science is notoriously hard" , "Self-propelled missiles" , "Spaceships" .)