You really need to keep a gardening notebook if you garden on any scale. You will want to know what the varieties are in your garden for yourself or the visitor who says "Ohhh what is that?"
In my early gardening days I used to do a "tour" for myself of my garden and I would name the plants to myself...the Latin Names!
I no longer know my plants so well after several moves (with many of my plants coming along with me each time).
If you keep a really nice garden notebook, you will always have your information at hand.
You can use any notebook, but in recent years I've come to like some of the notebooks meant for children who are learning to write that have a nice box every page or so for an illustration. In that box, you can draw your garden maps, attach seed packets, plant labels or photos from your garden. It is almost as if these little charmers are made for just this purpose!
Mead has a series of these notebooks which you can find at Target stores. Mine is "Redispace Transitional Storybook Paper" Here is an example of the brand (though not the one with space for drawings):
Here's what you want to be sure to include in a useful notebook:
A diary of your garden. What is blooming, what is thriving and what is not. At the beginning of a season I like to write what I want to accomplish or grow that season, which nurseries I hope to visit, any changes to gardens I want to make. At the end of the season I like to note which plants really did well and which underperformed or tragically died.
Seed packets, plant markers, lists of what you bought from local nurseries or mail ordered. That beautiful Texas Sage I had last year, where in the heck did I get that?
Maps that include where you plant bulbs, because you will ruthlessly dig those up every spring if you don't know where they are. Mark your perennials, because sometimes in the spring we are cocky and think we know what is a weed and what is a plant and oops!
If you wish to make snarky notes about your crow-like neighbor, this will amuse you when you re-read your notebook in the winter or the next spring.