Bloominous Stemples are unique plants found in Pikmin 3 and Hey! Pikmin. They are always found in caves, and will appear in a dormant state when first seen. In Pikmin 3, they will bloom if a light from a nearby electrode is activated, and once they bloom, they will not wither back to their dormant state. They work the same way in Hey! Pikmin, however they can also bloom if they receive light from sun or enemies that produce light (like Widemouthed Anode Beetles). If the source of light disappears, the plants will wither back to their dormant state. Once they bloom, they act as a path to access previously inaccessible places. According to the explorers in Pikmin 3, the surface of the Bloominous Stemple is very soft and fluffy.
A cluster of five is found in the Spotty Bulbear cave. Pikmin carrying objects can go over them, bypassing the fire hazards entirely, and they must be grown before any Pikmin, Winged Pikmin included, can access the Citrus Lump on the ledge behind the plants.
Two are found in the cave in which Charlie was first taken by the Vehemoth Phosbat. They allow Alph and Brittany to give chase to the Vehemoth Phosbat.
Two groups of two and one group of three are found in the second room of the oak, and each group requires its own electrode. Once all three electrodes are lit, the path beyond the Stemples can be accessed.