Sensible putting a boy in bulrush cover (8)
I believe the answer is:
reasoned
'sensible' is the definition.
(thesaurus)
'a boy in bulrush cover' is the wordplay.
'boy' becomes 'son' (synonyms).
'in' is an insertion indicator.
'bulrush cover' becomes 'reed' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'son'='ason'
'ason' going within 'reed' is 'REASONED'.
'putting' acts as a link.
Can you help me to learn more?
(Other definitions for reasoned that I've seen before include "Logically derived" , "Argued, concluded" , "Argued or deduced" , "Logically valid" , "Debated in calm and logical way" .)