Try This
Reprinted from the Rosebay, Massachusetts Chapter
For a simple yet durable label for your rhododendrons, use Dymo labeling tape. After embossing the name of the plant and any other pertinent information, roll out enough excess to fully surround the stalk, leaving plenty of room for future growth plus about two inches. Staple the ends together with an ordinary stapler after wrapping the tape around the stalk. DO NOT remove the white backing from the tape as this makes the label more durable. We have some labels which have survived for five years with only an occasional re-stapling required.