Said wrongly by the Yankee to be a bloomer (5)
I believe the answer is:
daisy
'a bloomer' is the definition.
(I know that daisy is a type of bloomer)
'said wrongly by the yankee' is the wordplay.
'wrongly' indicates anagramming the letters.
'by' is a charade indicator (letters next to each other).
'the yankee' becomes 'y' (phonetic alphabet: alpha, bravo, charlie etc.).
'said' with letters rearranged gives 'dais'.
'dais'+'y'='DAISY'
'to be' acts as a link.
(Other definitions for daisy that I've seen before include "Grassland plant" , "girl" , "Composite" , "Common wildflower" , "Lawn flower, weed" .)