James's first encounter with Weepinbell
James caught Victreebel as a Weepinbell sometime between So Near, Yet So Farfetch'd and The Breeding Center Secret. Prior to the latter episode, he left Weepinbell at a breeding center, unaware that it was actually a scheme by Butch and Cassidy. After searching, James located his Pokémon and discovered that it had evolved into a Victreebel.
Victreebel was only used once by James during his time in Kanto. In All Fired Up!, it was called out to help extinguish Meowth, who was on fire. However, instead of extinguishing the flames, Victreebel itself caught fire, and Ash needed to intervene with Squirtle to put it out.
In the Orange Islands, James started to use Victreebel in battle in place of Weezing, alongside Jessie's Arbok or Lickitung.
In addition to battling, Victreebel started to play a larger role in the team's plans. In A Way Off Day Off, James used Victreebel's Sleep Powder to put Ash, his friends, and all of their Pokémon to sleep in order to steal their Pokémon and get away unopposed. This failed, however, due to Snorlax being too heavy for them to steal.
During Johto, Victreebel became James's primary combatant. In The Fortune Hunters, Victreebel battled against Butch and Cassidy in an attempt to steal the Pokémon they themselves were stealing. While Victreebel made quick work of Cassidy's Raticate, James lost his energy and Jessie was forced to step in and use Wobbuffet, who ended up losing.
In Wobbu-Palooza!, Victreebel was used alongside Arbok to try to stop the Wobbuffet Festival crashers, since everyone else refused to fight due to the festival rules. Victreebel tried its best, but was easily defeated when overwhelmed by the thugs' Machoke and Primeape. Wobbuffet was sent out afterwards and managed to defeat them with his Counter attack.
In The Grass Route, James entered Victreebel in the Grass Tournament, hoping to win the collection of Leaf Stones. Victreebel went up against Ephraim and his Skiploom, nicknamed Skippy, in the first round. Despite hitting with its Vine Whip and Take Down, it was easily struck out of the tournament by Skippy's Leech Seed and being confused by a follow up Double Team.
In A Promise is a Promise, James used Victreebel against Butch and Cassidy to try and see which of them would steal a Lugia. The attacks from both sides of Team Rocket's Pokémon end up breaking the energy barrier holding Lugia captive and it blasts them all away.
In Here's Lookin' at You, Elekid, the Magikarp salesman encountered Team Rocket yet again, and upon an irate James demanding a refund for a prior purchase, offered to instead trade to them a Weepinbell for one of their Pokémon. He stated that Weepinbell's Sweet Scent move would help them to catch Pokémon, which convinced them it was a good deal, and got them thinking about which Pokémon to trade. Meowth refused to be traded, and Jessie and James each made it very clear they were unwilling to part with Arbok, Weezing, or Wobbuffet, which led to Jessie and Meowth volunteering Victreebel. James adamantly refused as he recalled all of their time spent together. Despite this, Jessie and Meowth forced him to make the trade anyway, though he was very unhappy about doing so.
Later, James's new Weepinbell unexpectedly evolved into another Victreebel while battling Ash and Casey. Immediately after evolving, the new Victreebel chomped down on Jessie, which caused her to order Arbok to send it flying, to James's dismay. At the same time, the Magikarp Salesman kicked James's first Victreebel away, coming to the realization that it won't obey him. The two Victreebel collided in midair, falling in love with each other at first sight. They were last seen skipping off together into the forest.
James mentioned Victreebel in the dub of Two Degrees of Separation! while Carnivine was biting on his head, stating that it wasn't the only Pokémon that showed affection towards him in such a manner. This mention didn't exist in the original Japanese version.
Victreebel reappeared in a flashback after Gardenia mentioned that the species was one of her favorites in The Grass-Type is Always Greener. She even offered to trade her own Victreebel to James for his Carnivine, but he declined.