On searching, as many others have, for a gardening diary of sorts I first of all came across this forum, then on further searching found this app:
https://www.gardenize.com/
I have only just downloaded it and have not fully tested it out yet, but it seems to tick many boxes. The app lets you record photos and details on individual plants or types of plants, planting areas and special events. Each can be cross referenced and the only cost appears to be if you want to export from the app in anyway.
