A flower sprung up (5)
I believe the answer is:
arose
'sprung up' is the definition.
(I've seen this in another clue)
'a flower' is the wordplay.
'flower' becomes 'rose' (I've seen this before).
'a'+'rose'='AROSE'
(Other definitions for arose that I've seen before include "Emerged from" , "Originated (from)" , "''. ... by any other name would smell as sweet'' (Romeo and Juliet)" , "appeared" , "Came about" .)