Go ahead, eat plants. Don't be surprised, however, if they decide to eat you. We keep them in pots, or a confined garden, but our plant friends may decide to roam, and eat. I guess that is only fair. We eat them, they eat us. One of my favorite Creature Feature films was 1967's "Maneater of Hydra" (aka "Island of the Doomed"). After all, the thirst for human blood spans all of nature. This film from Spain stars Cameron Mitchell in his finest performance.