Spring perennial (4)
I believe the answer is:
iris
'spring perennial' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for iris that I've seen before include "who keeps pupil in?" , "Part of the eye, usually brown or blue" , "Rainbow-goddess" , "pupil's governor" , "Coloured part of the lamp" .)