The old house we bought had metal miniblinds on all 26 windows, so I have enough to last a while. That was a great idea to take them to a plant swap! I'll do that!
I discovered my writing disappeared because I would pull the tag out of the ground to read it (rather than get down on my knees so I could be close enough to see) and when I rubbed the dirt off the tag, I was sanding the writing off! Didn't matter if it was permanent marker, paint pen or pencil. Then I discovered if I wrote the name on both halves of the tag--above ground and below, then I was sure to decipher it. The sun and rain weakened the ink or pencil, I think. The Brother labels stick just fine to miniblinds, so I use those now. Costs a little more, but it is much easier to read. Guess I could just write larger, but my iris, rose and daylily tags have plant name, hybridizer, year, and more. The metal blinds are wicked sharp, so if you have a choice...use the plastic ones.