Creeper I planted originally in ground close to hedge (9)

'creeper' is the definition.
(millipedes creep along)

'i planted originally in ground close to hedge' is the wordplay.
'originally' says to take the initial letters.
'in' is an insertion indicator.
'ground' becomes 'milled' (milling is a kind of grinding).
'close to' says to take the final letters (the 'close' to the word).
The initial letter of 'planted' is 'p'.
The final letter of 'hedge' is 'e'.
'i'+'p'='ip'
'ip' put inside 'milled' is 'milliped'.
'milliped'+'e'='MILLIPEDE'