rubber bands, zip ties, fishing line, thread, super glue(gel form), and scrubbie pads(netting)
all work great depending on what plant & where you want to mount them.
i have used them all and they all have their own benefits.
1. thread and rubber bands are great for anubis/java fern because after a while the
rubber band/thread will degrade and disappear and by that time the plants will have
attached themselves to the wood.
2. zip ties/ fishing line also work great for both rhizome and other plants except you
will have to remove them and zip ties can be ugly.
3. super glue is great for plants with rhizomes. it cures under water, is very strong and
you only need a little. too much glue and you will see the glue when it cures b/c it will
look white.(Loctite easy squeeze super glue gel... Cyanoacrylate is the main ingredient
and is fish safe.)
4. scrubbie pads/lufa netting is great for holding mosses down to wood until they grab
a hold themselves.