A flower came up (5)
'came up' is the definition.
(I've seen this before)
'a flower' is the wordplay.
'flower' becomes 'rose' (I've seen this in other clues).
'a'+'rose'='AROSE'
(Other definitions for arose that I've seen before include "Got out of bed" , "Came about" , "Issued" , "stemmed" , "Emerged from" .)
I believe this clue is a double definition.
'a flower' is the first definition.
(I know that rose is a type of flower)
'came up' is the second definition.
(I've seen this before)
(Other definitions for rose that I've seen before include "Flower - girl - got up" , "A flower; watering-can sprayer" , "Wine colour; plant" , "18 [ROSE]" , "beauty" .)