you can use a dab of krazy glue to attach the new lil plantlet to a rock or piece of wood. looks much better than string!
just take the plantlet out of the tank, remove as much of the dead leaf matter as possible, dab the plant with a paper towel to remove some of the water, make sure the area of the rock or wood you are gluing it to is somewhat dry, glob a little krazy glue on wood/rock, and hold the plant there until it's set and the glue is dry. put it back in the tank. tada! lol.
you can use any brand krazy glue or super glue. just be sure that the glue says cyanoacrylate on the label.