Being green is not exactly sweet (3)
I believe the answer is:
pea
'being green' is the definition.
'pea' can be an answer for 'green' (pea green is a kind of green). I am unsure of the 'being' bit.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for pea that I've seen before include "Legume" , "The plant is a strange ape" , "veg" , "garden plant" , "Edible green seed" .)