Get some Cole's Aluminum Identification Markers. They are aluminum foil and when you press on them with a pencil it leaves a permanent indentation. They also have an aluminum wire to attach the each marker to your plants. They last forever.

I've been thinking of getting some copper name tags from a firm in England. Were you impressed with the copper tag on your Fragrant Joy (you lucky thing) Pansyface?
I'm worried that there won't be enough contrast to read the indented name easily

I haven't seen the aluminum ones advertised in europe CamelliaJim, they sound good too

You are correct; the name is hard to read but it is definately permanent cuz it is 'engraved' in the copper. Not much room for additional info, though. The alum. ones sound like the same kind of thing. However, I would think the alum. would shine in the sun; like those icicles on a Christmas tree. I have found two sources for these hang tags; just not sure they are the answer. WWW.gardenmarkers.com and www.nothyme.com both here in the US.

I wonder about getting an engraving point - those little electrically operated ones - and engraving the copper, then filling the engraved bit with permanent marker ink. Perhaps this would give a clearer, neater wording and could be reinked occasionally and the copper polished to contrast...
Just thoughts at the moment