The Vridai in Strikeforce: fungal shapeshifters who spread like a virus, the more people know about them.
The Cotati in Empyre: Vegetable Aztecs from beyond space and time.
Terra Verde in X-Men: a place the Cotati would have just LOVED until recently...
The Gardener's spore on the moon: a world seed that takes the form of a woman made of plant matter.
Krakoa in the 616: As your average human sees it, a malevolently self-aware island that is home to a race of super-powered racist fascist communists who are always plotting the downfall of all of humanity when not having orgies, eating human babies, or simply mocking God by existing.
Five storylines featuring sentient plant life, plant-based tech, plant-based villains (or perceived villains), or plant-based medicine's and infections.
Why does Marvel hate plants so much?