I accidentally ended up creating some notes in the Gmail Notes inside my iDevice only to be completely confounded by the fact I could not see them in my desktop. I tried to find some resolution by looking at the instructions for the Apple notes, but got frustrated with the lack of information.
So, here it is how I solved my issue:
It seems that as an Apple Notes user, one can select to have the Notes saved “On my iPhone/iPad/Mac” or synced to any email account of one’s choice. If you chose the first option, then no issues there, but the “fun” part comes with the latter. In that case the application will send notes from the device via Gmail to the Gmail servers, or for that matter to the email account you designated under IMAP. This means that your notes are therefore treated as normal email and labelled as “Notes”. Not only that, they are automatically archived on arrival. The initial transfer is one-way only and this implies that the notes can’t be restored from Gmail to the device. In order to find your Notes in Gmail you have to search for the “Notes” label!
If you call up your note on your device, the application access it from Gmail and displays it. But if you deleted it, as many of us do, then the app gets confused as it does not know where they are… If they are deleted from the device removes the label in Gmail and thus they cannot be accessed by the device and they get zombiefied in Gmail! They will still be present in All Mail, but without label.
How to fix this… well it depends. If the Notes have been deleted from the Gmail account from the web interface they will still be there in the Trash for 30 days. You can “restore” then during that time and will be showing in the Notes App on the device.
If the Notes folder was deleted using the Mail App on the device, the notes will (probably) still be there under “All Mail” but without a label. You can search for them and re-apply the label!
My advice would be not to use the synching at all… it has caused more pains than it should be. Let me know if this helps.