Cleaner with cluster of hair is a weedy type (8)
I believe the answer is:
charlock
'a weedy type' is the definition.
(charlock is a type of weed)
'cleaner with cluster of hair' is the wordplay.
'cleaner' becomes 'char' (char can mean a cleaner).
'with' is a charade indicator (letters next to each other).
'cluster of hair' becomes 'lock' (a lock of hair).
'char'+'lock'='CHARLOCK'
'is' is the link.
(Other definitions for charlock that I've seen before include "Wild Mustard" , "Plant growing wild" .)