Woody grass (6)
I believe the answer is:
bamboo
'woody grass' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for bamboo that I've seen before include "Treelike tropical grass" , "Tropical cane with hollow centres, used for furniture" , "Tropical grass/wood" , "Panda's dinner?" , "Woody grass plant" .)