Spiny succulent (6)
I believe the answer is:
cactus
'spiny succulent' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cactus that I've seen before include "Drought-resistant plant" , "Eg, prickly pear" , "Desert flower" , "Thorny desert plant" , "plant, succulent one" .)