Hurry to see a marsh plant (4)
I believe the answer is:
rush
This clue is a double definition.
'hurry' is the first definition.
(I know that hurry can be written as rush)
'marsh plant' is the second definition.
(I know that rush is a type of marsh plant)
'to see a' is the link.
(Other definitions for rush that I've seen before include "Hasten; plant" , "Move hastily; plant" , "Hurry to the river grass" , "Take by storm" , "Hurry to the wetland grass" .)