Perennial plants with spikes of flowers (8)
I believe the answer is:
gladioli
'perennial plants with spikes of flowers' is the definition.
(iris family, sword like leaves, flower spikes)
This is the entire clue.
(Other definitions for gladioli that I've seen before include "Garden plants of the iris family" , "bloomers!" , "Plant with brightly coloured, funnel-shaped flowers" , "I laid log in the flowers" , "Did the Iliad log out these flowers?" .)