Climbing plant with a dye-yielding root (6)
I believe the answer is:
madder
'climbing plant with a dye-yielding root' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for madder that I've seen before include "Made even more angry by the red dye" , "more bananas" , "More angry or frantic" , "Rot" , "Plant; more angry" .)