I use the Sharpie Silver Mettalic as previously recommended. I use it for everything outside I label. That marker does not sun bleach at all. In the past before using this marker, I had several fig tags that faded that I had to try to figure out what they were, and they were written in black permanent marker that faded in the sun. But never with this silver marker. I double label all my figs and citrus now, I make one nice label with a P-touch label, and make a second label with the silver Sharpie that I shove all the way down in the dirt just incase the other label gets misplaced somehow. And there were several times I was thankful for it! I have stuff labeled for atleast 4 years in the sun, and the Silver Sharpie is still there with no sun fade,
When I start cuttings, I put initials on my cuttings with the Silver Mettalic Sharpie too and never had a problem. Also a hint, I use a notebook and write a key for the initials with its name and source and/or number just incase I forget what the initials stand for I can always go back and look it up,
Christy