I know it is difficult to find time to update your garden journal, but even if it’s a couple of weeks after the work, making notes which you will understand a year from now can help you in the long run.
Some of the the things I record are dates of transplants and the health of the plant at that time; new plants added to the garden with the correct botanical name; date of last watering in the fall; major pruning of trees; insect infestations and the overall growth of the garden that year. Also worthy are the highs and lows of the season such as: the chrysanthemums flourished in their new loaction and I need to remove one in the spring; the snapdragons bloomed all season in the new sheltered location or wind ripped the leaves on the tomatoes and decapitated my Asiatic Lillies.
It is worth the effort to keep a journal. Not only is all your information in one location you’ll be able to look back and see how your garden has grown.