Poisonous flowering shrub (8)
I believe the answer is:
oleander
'poisonous flowering shrub' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oleander that I've seen before include "Reloaned for evergreen shrub with bright flowers" , "Poisonous evergreen shrub with white, pink or red flowers" , "poisonous plant" , "Red alone (anag.)" , "Flowering shrub from olden era, oddly" .)