I have done something similar for years. I bought a box of plastic knives - like you would take on a picnic at Sam's Club. Box of 500 I think. I put the name on the blade with a sharpie then put a piece of the clear scotch tape over it. The tape helps the marker to stay on. Then I put the knife horizontally in the hole when planting daylilies.
I use AAA Engraved markers now on the daylilies so I actually have not done this in some time.
I did dig up a clump with a knife under it a year or so ago - it had been under there for at least 15 years, and could still be read.
