Shrub of the dogbane family, with lance-shaped leathery leaves and ornate red or white flowers (8)
I believe the answer is:
oleander
(Other definitions for oleander that I've seen before include "Reloaned for evergreen shrub with bright flowers" , "Flowering shrub from olden era, oddly" , "Red alone (anag.)" , "Adore Len (anag.)" , "tree" .)