In her debut appearance, Venusaur as a Bulbasaur is shown to be protective when she protects May from other grass Pokemon from attacking her.
Like Clair's Dragonite, Bulbasaur is also fond of flowers, showcasing her sweet and kind personality. She is also very confident when she enters most of the Contests except the first Contest where she shows her nervousness.
She is also strikes up her friendship with other Pokemon especially Ash's Bulbasaur. Her friendship with Ash's are demonstrated in Hokey Poke Balls as Ash temporarily brought his Bulbasaur to May's in Hoenn as the two are playing together and they are a very friendly terms when they teamed up to stop Team Rocket. Their friendship bond continues in The Right Place and the Right Mime where May decides to let her Bulbasaur stays at Professor Oak's lab to learn more on Ash's Bulbasaur until she evolves twice from her evolutionary stage.
As a Venusaur, it become another of May's powerhouses before May's Blaziken.
Ruby and Sapphire series
Venusaur was caught as a little Bulbasaur which lived with many grass Pokémon in a special territory led by a wild Venusaur. As May ends up in the forbidden area she is chased by the grass Pokémon, but is saved by the little Bulbasaur who eventually joins her team when May is about to leave. Bulbasaur came as a big help to her team with the learned move Petal Dance which was used with a lot of elegance.
She was sent out by May in Hokey Poké Balls to enjoy the sightings of the city, though she was distracted by some flowers in a truck but was eventually rescued as the truck speeds off. She was taken to Professor Oak in the Pokémon Center and Ash later arrives. However, the Poké Balls were stolen by Team Rocket so she teams up with Ash's Bulbasaur to find and retrieved the stolen Poké Balls. During the fight against James' Cacnea and Jessie's Seviper, she is unable to negate their attacks as Ash's Bulbasaur manages to negate with its Vine Whip. Altogether, both Bulbasaurs manages to knock them off with their Vine Whips and retrieving the stolen Poké Balls before Pikachu blasts them off with its Thunderbolt. Afterwards both Bulbasaurs does a high five with their vines. Before Ash's Bulbasaur is about to be transported back to Professor Oak, it patted her to say goodbye and she was given a positive thinking after Ash's had finally transported.
She later appears in Cruisin' for a Losin'. While she is waiting in the backstage, May has a short argument with Ash, saying that she cares a lot for Bulbasaur. May's anger made her confused. When it was May's turn. She was called in to battle Lairon. However, she gets scared since she is not used to being in a stage fight. She reluctantly battles Lairon but gets knocked out, causing her trainer to lose the match.
In the The Right Place and The Right Mime! She finally reunites with Ash's Bulbasaur as both Ash and May releases their Pokemon to meet all of Ash's Pokemon living at Professor Oak's lab. Both Bulbasaurs teaming up with the other Pokemon to fight off Team Rocket. After Team Rocket is blasted off, May allows her Bulbasaur to stay at Professor Oak's lab to learn more from Ash's Bulbasaur.
Diamond and Pearl series
Bulbasaur acknowledged Ash's Bulbasaur as the two are good friends. May makes a comeback in Sinnoh saga revealing her new Pokémon and discovers that Bulbasaur evolved twice during her trainer's journey in Johto. Venusaur was now seen fighting a Trainer's Marill during the Wallace Cup.
- Bulbasaur is the first Kanto starter Pokémon May has.
- Unlike other Bulbasaur, May's Bulbasaur has a different pattern on her forehead which is shaped a bit like two hearts stuck together.
- Venusaur's capture as a Bulbasaur marked the first time in which one of Ash's friends caught a Pokémon that he had previously owned.
- Venusaur as a Bulbasaur is the only Pokémon May owns who didn't appear in Pokémon: Battle Frontier.