I use white grease pencils (china markers) on my black pots. The only ones I've had a problem with was writing the name on a pot that was really old and getting the "oxidation look". If I have not made a tag for a planted iris I just put some dirt in the marked pot and place the pot just behind the iris until I get the tag made. Not the nicest look for the yard but doable until the tag is made. I will have to post a picture of my tags I make (I think they will be around long after I' m gone).
Barbara
