Wonderful idea! I often use these metal markers, they are zinc plates that are on heavy wire stakes. You write on them with a -#2 lead pencil, however I have discovered the writing seems to be quite permanent as I cannot get it off the plate once I've written on it. What I have learned to do is to number the stakes, then map or list the plants by number keeping a list or map with the plant listed by the number of it's stake. Then if you lose that plant, you just plant another plant and change the name on your list. I get my plant stakes off eBay.
