Tapu Bulu is a bit laid back as it's seen napping and is physically really strong able to carry a huge tree with ease. It's greatly impressed by feats of determination when it saw Ash trying to calm down his enraged Lycanroc. Tapu Bulu gives those its praise and recognition by clapping its arms.
Tapu Bulu reappeared at the Altar of the Sunne on Poni Island with Tapu Koko, Tapu Lele, and Tapu Fini. It revealed to Ash and the gang that they were the ones who brought Nebby to Melemele Island where Ash can find it and take care of it. After Ash told them about Nebby's motionless evolved form, Tapu Fini and Tapu Lele perform a ritual around Nebby. With the ritual complete after a few minutes, the Altar of the Sunne activated itself and Nebby evolved into Solgaleo. The Tapu Guardians then gave Ash the Solganium Z, but the only problem is that it won't fit on his Z-Ring. Tapu Koko resolves the problem by taking the Z-Ring, and through a special dance, it and the other Tapu Guardians upgraded it into a Z-Power Ring. It then watched as Ash and Nebby performed the Z-Move, Searing Sunraze Smash, and enter the Ultra Wormhole to rescue Lusamine from Ultra Deep Sea. After that, the Tapu Guardians went back to their respective islands.
Tapu Bulu reappeared again as it was minding its business, napping in the Ruins of Abundance. When Ash and his Pokémon made some failed attempts to wake it up, Poipole got its attention by spraying it with its liquid. It demonstrated its power as it plows through the ground, plants some seeds and grows several trees. As it rests in the trees, Rowlet decides to sleep in the trees as well. But Tapu Bulu gave the trees some much power that Rowlet began absorbing it, allowing it to learn Razor Leaf. Clouds rolled by and it started to rain soon after. Tapu Bulu watched as Ash and his Pokémon played in the mud puddles. It gave Ash's Lycanroc a gentle push and knocked it into the mud puddles. As Lycanroc went berserk and prepares to attack the group, Ash stopped it by grabbing its face and reminds it of the good times they've shared together just as the rain stops. Touched by Ash's determination of helping his Pokémon, Tapu Bulu challenged them to a battle. During the battle, Lycanroc was knocked into a pond. Instead of going berserk, it continued the battle, which made Tapu Bulu happy now that it got over its aversion of getting dirty or wet. Tapu Bulu proved to be a powerful opponent, but to its surprise, Lycanroc learned Stone Edge and knocked it over. Tapu Bulu called off the battle and congratulated Ash and Lycanroc on their improvement. Tapu Bulu then gave Ash and his Pokémon oran berries as a reward for their hard work and it went back to sleep.
At some point during the Alola crisis, Tapu Bulu watched Nanu from a distance as he observes the sunrise during the Manalo Festival.Tapu Bulu later helped join everyone in sharing its light to restore Necrozma's original Ultra form.