moss or flower bomb on vertical surface

Hello! I am relatively new to the site, so please direct if I am in the wrong place.

I have had an idea for a while and would like some help.

I've gotten into wheat pasting and have an idea for a vertical flower bomb (or maybe a moss bomb would be hardier?) that would be able to survive in a wheat paste medium. I am also open to other mediums.

I have heard that blending butter milk with moss can help it grow?

I am in the Northeast; PA, USA.

Please any and all ideas, share 'em!

Thanks a ton,
Bobby

Welcome to Permies Bobert!
The first think I think of for this is mosses effectively have tiny seeds, and are adapted to clinging to surfaces.
I don't know how big their seeds are, but
epiphytic orchids might do the trick.
I think adding a bit of clay to the mix might help a plant seed or moss spore get established.
Speaking of spores, I bet there are fungal spores available that would love  wheat paste!