~ What ? ~
A note is evergreen when it is self-containing. It hold all the needed information to describe an idea, has a place in the vault, contains all the needed metadata.
Process
Whenever a note is created, a status of seed is added. As the note matures and progresses, the state of the note will keep changing. The seed will grow to a sapling when we start populating the note with data. The sapling will eventually become a tree where it still needs more information added to it, but has become substantial enough. At the end, it joins the evergreen forest. After a while, some notes may become withered, as they are no longer needed.
Some notes were never meant to joint the forest. These are ephemeral notes and information in them is either not important or temporary, or it should be moved immediately to another place.
Some notes need a place, but you just can’t figure it out atm, so they are put in an inbox.
And finally some notes don’t really need a place… they are orphans.