I'd say toss some plastic ones in there and see if they still attack em. You can get relatively real looking artificial plants for cheap. thats all I have right now and the tank is doing great. Plus from the current of my filter and aeration they almost look real the way they move.
Well i had two large (not to mention expensive) java ferns on wood that are reduced to stumps and i know i haven't syphoned it all out so i guess they are eating most of it! I was under the impression that it had a nasty flavour aswell, i guess i'll go back to silk/plastic!