Quietly fix the hedge? (6)
I believe the answer is:
privet
'the hedge?' is the definition.
(I've seen this before)
'quietly fix' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'fix' becomes 'rivet' (riveting is a kind of fixing).
'p'+'rivet'='PRIVET'
(Other definitions for privet that I've seen before include "Hedge for pert Vi" , "Hedging shrub" , "Shrub much used for hedges" , "Bushy evergreen shrub used for hedges" , "hedge material" .)