Era not quite so evergreen (7)
I believe the answer is:
ageless
'quite so evergreen' is the definition.
'ageless' can be an answer for 'evergreen' (evergreen can mean ageless or fresh). I'm unsure of the 'quite so' bit.
'era not' is the wordplay.
'era' becomes 'age' (both can mean a long period of time).
'not' becomes 'less' (I've seen this in other clues).
'age'+'less'='AGELESS'
Can you help me to learn more?
(Other definitions for ageless that I've seen before include "Staying young" , "impossible to date" , "Not growing older" , "Ever youthful" , "Never growing old" .)