For one to call out wrongly is a bloomer! (5)
I believe the answer is:
lilac
'a bloomer' is the definition.
(flowering plant)
'for one to call out wrongly' is the wordplay.
'for one' becomes 'li' (I can't explain this - if you can you should believe this answer much more).
'to' means one lot of letters go next to another.
'out' means to remove the last letter.
'wrongly' indicates an anagram.
'call' with its final letter taken off is 'cal'.
'cal' with letters rearranged gives 'lac'.
'li'+'lac'='LILAC'
'is' is the link.
Can you help me to learn more?
(Other definitions for lilac that I've seen before include "garden ornamental" , "Shrub or small tree with fragrant blossom" , "Tree with pink blossoms" , "I call (anag)" , "Lavender-coloured" .)