Plantbending is the ability to manipulate plant life from the highly water-saturated vines and roots found within the swamp lands and seaweed from the ocean floor. It is done by bending the ample amounts of water within them just as with watery mud. Huu made this technique his signature move by covering himself in vines and other plant life to create a monstrous-looking being that was capable of lifting heavy objects.
Going further, a skilled waterbender is able to separate and completely extract the water from plants for more effective utilization just as they are able to separate the water from mud, sand, polluted river systems, etc. This process will then leave behind the withered remains of all the affected plant life or, in the case of large trees, cause them to fracture as Hama demonstrated with her degenerated views.