Heath, one Conservative hampered by time (5)
I believe the answer is:
erica
'heath' is the definition.
(erica is a kind of heath)
'one conservative hampered by time' is the wordplay.
'one' becomes 'i' (Roman numeral).
'conservative' becomes 'c' (abbreviation commonly used in UK politics).
'hampered by' is an insertion indicator.
'time' becomes 'era' (I've seen this before).
'i'+'c'='ic'
'ic' put within 'era' is 'ERICA'.
(Other definitions for erica that I've seen before include "Heathland shrub; girl's name" , "ling" , "Woman" , "Girl's name - I care (anag)" , "Moorland plant, girl's name" .)