Michaelmas daisy (5)
I believe the answer is:
aster
'michaelmas daisy' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for aster that I've seen before include "Flowering plant; tares (anag.)" , "Flower of the daisy family - rates (anag)" , "Tears (anag) - plant" , "eg Michaelmas daisy" , "It grows" .)