Think garden feature needs trees around at intervals (6)
I believe the answer is:
ponder
'think' is the definition.
(pondering is a kind of thinking)
'garden feature needs trees around at intervals' is the wordplay.
'garden feature' becomes 'pond' (I've seen this in another clue).
'needs' is a charade indicator (letters next to each other).
'around' indicates the central letters.
'at intervals' becomes 'r' (I can't justify this - if you can you should give a lot more credence to this answer).
The central letter of 'trees' is 'e'.
'pond'+'e'+'r'='PONDER'
Can you help me to learn more?
(Other definitions for ponder that I've seen before include "Think deeply about, ruminate" , "Weigh in the mind" , "Consider deeply" , "Muse" , "4 down" .)