Noted flower, an annual (6)
I believe the answer is:
easter
'an annual' is the definition.
'noted flower' is the wordplay.
'noted' becomes 'e' (I am not sure about this - if you are sure you should believe this answer much more).
'flower' becomes 'aster' (type of flower).
'e'+'aster'='EASTER'
Can you help me to learn more?
(Other definitions for easter that I've seen before include "Teaser about Christian festival" , "Festival after Lent" , "Christian festival in Spring" , "Christian celebration for Teresa" , "holiday time" .)