I'm thinking of rolling some plastic mesh into a cylinder, and planting moss through it. The moss should grow through the mesh and completely hide it after a while. I might suction cup it to the tank side to keep it off the ground, to make it less likely that my shrimp will hide in it and become a snack.
I think that's what I am going to do with Algernon's tree. He's getting a driftwood/moss tree.