Environmental flower starts in the shade (4,5)
I believe the answer is:
nile green
'the shade' is the definition.
(I have seen 'A shade' mean 'nile green' so perhaps 'shade' could also mean 'nile green')
'environmental flower starts' is the wordplay.
'environmental' becomes 'green'.
'flower' becomes 'nile' (Nile River is an example).
'starts' means one lot of letters go next to another.
'green' after 'nile' is 'NILE GREEN'.
'in' acts as a link.
(Other definitions for nile green that I've seen before include "Pale shade" , "Pale colour" .)