Fly through plant in the swamp (4)
I believe the answer is:
rush
'fly' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for rush that I've seen before include "Be too hasty or too fast" , "Stampede - marsh grass" , "candle" , "Dash to the grassy plant" , "Charge" .)