Moss type plants on rock wall ?

I would appreciate it if only people who have/did this answer this. Some plants grow

on rocks/wood and I've noticed that most which do have the word "moss" in the

name somewhere. Lets say I have a tall pile of rocks against one wall and would

like to put/grow maybe Java Moss on it. Would you start a piece of it at the bottom

against the wall or would it be better (as far as it being closer to the light) to try

to get it started at/near the top of the wall ? The type I have is Tricho.

http://www.ebay.com/itm/250647897535?ssPageName=ST...

I really don't even know if it will grow on a vertical wall but we'll see. I placed it

on the bottom against the wall in hopes that it would go up the wall as it spreads.

But if anyone has experience/w this type and knows that it will I'd like it if I

could here from you on this.