I want to attach outdoor Christmas lights to a mortar retaining wall without damaging the wall. Suggestions?

Question

The wall is thin mortar over cinder blocks. I worry that it will split if I use mortar nails. But tape is so ugly and doesn't always hold.

Answer 1

3M makes some hooks that should work for you. They have adhesive backs and are supposed to stick well, yet remove easily.

Answer 2

plastic hooks with a sticky back just hang the wires on them, you can even paint them to match your house. no one will ever know they are there.