Rushlike plant (5)
I believe the answer is:
sedge
'rushlike plant' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sedge that I've seen before include "Coarse grassy plant" , "Plant like grass" , "fly by rivers" , "Bog plant; type of warbler" , "water-loving vegetation" .)