Idyllic garden some enjoyed enormously (4)
I believe the answer is:
eden
'idyllic garden' is the definition.
(I've seen this before)
'some enjoyed enormously' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'EDEN' can be found hidden inside 'enjoyed enormously'.
(Other definitions for eden that I've seen before include "The original garden?" , "Biblical garden" , "prime minister in the past" , "Someone once seen in Number Ten's" , "The first garden" .)