Weather-proof way to add privacy to glass

No, the entire window will be outside. I am going to have them in a frame and freestanding in between some planters of bamboo. I want the whole line of bamboo, windows, bamboo, windows, bamboo to act as an organic privacy screen on the north side of my property. Our neighbors front porch is close to and facing two of our bedrooms and our bathroom, and I would like to have privacy when our windows are open, and not have to have curtains or blinds blocking all of the light.

Etching would be waterproof. But you might have little pieces of stuff like dirt, algae, moss. etc grow in the tiny grooves created when you etch glass. Perhaps there are decals that can be put on the glass? I'm not sure that painting would last. Someone that knows about outdoor paints would be able to help you.