When the Venus flytrap closes shut on a tasty bug meal, for example, it releases chemicals that liquefy all the soft parts. The plant eats the delicious juice, but opens back up to let the crunchy bits fall out. Those solids are waste, and could be considered plant poop. Pitcher plants, on the other hand, keep those crispy parts at the bottom of the pitcher tube, where they rot with the help of microbes until they are gone or that particular leaf dies. So instead of pooping, they turn part of their bodies into a septic system. Yum!
Of course, plants also suck in carbon dioxide from the air and push out oxygen in the amazing process called photosynthesis, but this is probably more like breathing—so we’re not breathing plant poo. They also give off extra water through their leaves, but that’s not quite right either, more like sweating or peeing.
More poop-like is a plant’s ability to get rid of salt, metals, and other stuff by spreading it through its leaves, bark, heart wood, and roots.