Come into flower (7)
I believe the answer is:
blossom
'come into flower' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for blossom that I've seen before include "Mature promisingly" , "Come into flower" , "Flowers on tree or bush" , "Flowers (on tree, shrub)" , "Girl - flower(s)" .)