I use old, discarded aluminum venetian blinds with the baked-on enamel
paint, cut into appropriate lengths. I write the label on one side with a
permanent marker, and scratch the same info on the other side with a
nail. You can either attach with a tack, brad, wire, or cable tie, or
stick it in the soil next to the trunk.
Lucky Pittman
USDA Zone 6
Hopkinsville, KY