Never thought of a piranha plant and venus fire plants works so well without to having them to be a hurtful plants with mouths... but having them no mouths what so ever and work as background decorations. This is a very cool idea. Definetly a useful and clever graphic.
These are quite interesting. I think a good use for the ground leaves would be to place them over a Volcano Lotus, then when it is killed, the leaves are still there.