Cassava (5)
I believe the answer is:
yucca
'cassava' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for yucca that I've seen before include "North American evergreen plant with sword-shaped leaves" , "Plant of agave family" , "Plant of the Agavaceae family" , "The Joshua Tree'" , "Adam's Needle plant" .)