Cuckoo seen in borders of desolate wild garden (8)
I believe the answer is:
deranged
'cuckoo' is the definition.
(thesaurus)
'borders of desolate wild garden' is the wordplay.
'borders of' means to remove the middle letters.
'wild' indicates an anagram.
'desolate' with its centre taken out is 'de'.
'garden' is an anagram of 'ranged'.
'de'+'ranged'='DERANGED'
'seen in' is the link.
(Other definitions for deranged that I've seen before include "Disordered; insane" , "Disordered, mentally perhaps" , "totally without reason" , "What Ophelia was eventually" , "Crackpot" .)