Headgear not raised in the Garden! (6)
I believe the answer is:
hatton
'raised in the garden' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'headgear not' is the wordplay.
I cannot really understand how this works, but
'headgear' could be 'hat' (hat is a kind of headgear) and 'hat' is present in the answer.
an anagram of 'not' is 'ton' which is present in the answer.
No letters remain.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for hatton that I've seen before include "London centre of diamond trade" , "London garden for diamond merchants" .)