My caveat to this thread is that all my plants are container plants, though the majority of the year, those plants (and their associated plant labels) are outside in the weather.
I use aluminum from drink cans for my plant labels. It is not so thick that it cannot be embossed into but is thick enough that it will withstand wear. I cut the top and bottom off the can, then unroll and flatten the side. I use an empty ballpoint pen (empty because I do not want ink getting all over the place) and place the aluminum on a surface with some give, not a hard surface. On my labels, I write the scientific name, common name or names, date I acquired the plant or seed, and who I acquired it from. I engrave this information lightly with my first pass, then do a second pass to engrave everything more forcefully. It takes a little bit of time and hand strength to do this, but not as much of either as you might think.
Here is what one of those labels looks like. Note that I cut off the corners to make them safer to handle.
I place them in my plants in a variety of ways. The most common and easiest is to use a thick piece of aluminum wire. I make a loop at the top for the label to go on and then stick it down into the pot. The wire needs to be long enough to anchor itself down in the pot and of a thick enough gauge not to bend too easily. I always use aluminum wire for my aluminum tags to prevent any galvanic corrosion, which would reduce the lifespan of the tags.
Sometimes, I make small cedar posts for the tags to go on. Cedar is very rot resistant, but it will rot eventually, so this is not the most permanent post material.
Other times, I use other forms of aluminum. This post was made out of an aluminum storm window.
This shows what my plant labels and posts look like after several years of use. This is one of the first of these I made, back in 2020. I was still figuring things out, so it is not the best label. Although I did not photograph the back of the label, after a couple of years, whatever drink advertising that is on the reverse will fade away in the sun and become pretty much unnoticeable.
