I have see fine plant markers that have been in use for years. The last few years I have been ordering stainless steel from Amazon in the 20" length as I like a longer marker.
https://www.amazon.com/dp/B00F86AJYI/ They come in 25, 50 and 100 packages, I like the way the label plates are held on these they do not fall off the way the see fine do sometimes then I take a pliers out and recrimp them back on the galvanized heavy wire.
