Arrived, returning a sick plant (8)
I believe the answer is:
camellia
'plant' is the definition.
The answer is an example.
'arrived returning a sick' is the wordplay.
'arrived' becomes 'came' (come can mean to appear or arrive).
'returning' says the letters should be written in reverse.
'sick' becomes 'ill' (similar in meaning).
'a'+'ill'='aill'
'aill' written backwards gives 'llia'.
'came'+'llia'='CAMELLIA'
(Other definitions for camellia that I've seen before include "Ornamental shrub with rose-like flowers" , "Shrub related to tea plant" , "Lima lace (anag) - evergreen shrub" , "Showy evergreen shrub" , "Shrub with showy flowers" .)