I'd use a paint pen over a sharpie.. although I'm not sure what a professional sharpie is.. I've found in the past, that pencil on zinc markers lasts longer than any other type of marker (grease pen, sharpie, paint pen). The problem is that they are not easy to read with age (mine -or- the labels
).. I've tried the copper faced labels.. Again, although they are embossed and last, you have to get down on your hands and knees to read them, and hope you've got your reading glasses with you.
I started using the brother's P-touch labeler a few years ago and sticking them on metal markers I get from Paw Paw Everlast Co. You can get essentially the same product from Kinkaid or Lee Valley, but Paw Paw always ships very quickly. I think their prices are similar. Time will tell how well they last, but the 2 and 3 year old tags so no sign of wear yet..
Leon, You didn't say what labeling system you used, or how long you've had the labels. Your pictures show cultivars from the 80's.. If you've had them for 25 years, that's pretty impressive, really...
