African native bloomer on the banks of one river (7)
I believe the answer is:
giraffe
'african native' is the definition.
(animal native to Africa)
'bloomer on the banks of one river' is the wordplay.
'bloomer on' becomes 'gaffe' (I am not sure about this - if you are sure you should believe this answer much more).
'the banks' is an insertion indicator (bank can mean to surround or border).
'of one' becomes 'i' (I've seen this in other clues).
'river' becomes 'r' (abbreviation for river).
'i'+'r'='ir'
'gaffe' going around 'ir' is 'GIRAFFE'.
Can you help me to learn more?
(Other definitions for giraffe that I've seen before include "Tallest extant quadruped" , "Animal once known as a camelopard" , "Long-necked animal" , "The tallest animal with long neck" , "The animal might fear fig" .)