Evergreen - Oxford English Dictionary
You cannot do better than the OED for defintions.
Pic 1: potentially relevant defintions
Pic 2: screenshot of the book in the citation from the OED
>Of all the trees, none but the evergreen tribe will keep their integrity.
"Brother Jonathan: Or, The New Englanders" Vol II, p.31
https://archive.org/details/brotherjonathan01nealgoog/page/n38/mode/2up/search/evergreen
Pic 3: also, google "evergreen defintion" (without the missing 'i'), you get an add for hotel room that gives a defintion related to evergreeness. Might be irrelevant, but including for completeness.
https://www.almhaus.it/en-apartment-brunelle.html