Bush, the rock ’n' roll pioneer? (5)
I believe the answer is:
'bush the rock' is the definition.
'holly' can be an answer for 'bush' (holly is a type of bush). I am not certain of the 'the rock' bit.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for holly that I've seen before include "Shrub with red berries" , "Shrub with scarlet berries" , "Ilex is its genus" , "Evergreen tree with spiky leaves" , "It has red berries and glossy leaves with prickles" .)