The plants live with, and were developed by, Crazy Dave, his niece Patrice, and her friend Nate, using Dave's "unique plant food and special fertilizers." They fight the zombie hordes of Dr. Zomboss.
The plants include many of the plants seen in the Plants vs. Zombies video games, including Sunflowers, Pea Shooters, Bloomerangs, Squash, Wall-Nuts and Tall-Nuts, Magnet-Shrooms, Bonk Choy, Citrons, Laser Beans, Melon-Pults, Gatling Peas, Three-Peaters, Blovers, Cherry Bombs, Chompers, Cactuses, Snow Peas, Jalapenos, Spikeweeds, Kernel-Pults, Cattails, Magnifying Grass, Snow Peas, Potato Mines, Blovers, Split Peas, Starfruits, Pumpkins, Winter Melons, Umbrella Leaves, Garlics, and others.
Some individual named plants include Fred the Sunflower, Jeff the Bloomerang, and Grrawrr-Bear the Ultimate Face-Puncher, a Bonk Choy. Rose and Citron are plants from (respectively) the past and future.
The plants usually follow the leadership of Nate and Patrice, fighting as their army.
Major Story Arcs
An army of zombies invades Neighborville and only Crazy Dave's plants, along with Patrice and Nate, can stop them. Nate and Patrice learn the origin of the plants: Crazy Dave has been creating them for years, knowing that Neighborville would eventually be invaded. He has been seeding them throughout the town as a precaution. Nate and Patrice lead the plants against the zombies, but the zombies numbers are overwhelming, and Zomboss uses a machine to blot out the sun, draining the plants of the power. However, Dave uses a giant windmill to blow the clouds away, and the plants save the day.
Zomboss created a sun vacuum to destroy the plants by taking away their power source. Luckily one of his own zombies accidentally destroyed, sending its parts throughout time. Crazy Dave, Patrice, and Nate go in search of the pieces to stop Zomboss from reassembling the machine. The plants go along to help, and do the majority of fighting with the zombie armies.
When the kids visit the Jurassic era, they meet a group of giant sentient, powered plants that are native to the era, showing that while Crazy Dave has honed their evolution in our time, he did not create them from scratch.
Bully for You
When both Zomboss and the Anti-Bullying Squad attempt to take over Neighborville with competing zombie armies, the plants once again work with Nate and Patrice to protect the town.
Grown Sweet Home
When Crazy Dave gets out of control making new inventions, the plants decide to move to the old family mansion. Living on their own for the first time, they get a little out of control themselves. Patrice, Nate, and Dave try to show them how to be more responsible, and to act more like humans. They have little success at first, but eventually an incentive program proves more successful. They eventually go into town to test their human-imitation skills, but run into the zombies, who have been doing the same thing. They have a contest to be the best at copying people, and the plants do well, but it ends in a tie. The zombies later attack, and the plants do their best to fight back, but the zombies are winning. After showing Zomboss that the zombies have been stealing his Pop Smarts, the zombies turn on themselves, and the plants win.
Petal to the Metal
Nate and Patrice try to show the plants how to drive, but they're not very good at it. Unfortunately, Zomboss and his zombie army invade Neighborville once again, this time with a fleet of souped-up cars. Naturally, Nate, Patrice, and Crazy Dave challenge them to a race, and the plants join in as the crew on their Ice-Cream Racer car. The car is solar-powered, and the Sunflower plants help it go. The kids don't trust Crazy Dave's driving abilities, especially since he hasn't had any sleep, so they want to get the plants to drive, but as the earlier lessons showed, they can't do it.
Nate decides the best way to win is to board the zombies' cars, so the kids and the plants attack, and manage to defeat the zombie driving teams. They return to Neighborville and find another zombie army there, which they challenge to another set of races around town. They win, except that Mr. Stubbins hitches a ride on the front of their car, making it a tie.
Boom Boom Mushroom
When Zomboss decides to drop Neighborville below the surface into a system of caves, the plants assist Nate and Patrice in their quest to find Boom Boom Mushroom, a secretive plant with the power to destroy Zomboss's plans.
They ultimately trick Zomboss and the zombies to go up to the surface, where the plants bombard him in peas and defeat him.
The plants are largely overrun by the zombies in their future Z-Mech suits, until future Patrice and Nate, Crazy Dave’s burping frogs, the magical Rose, and the future-tech Citron manage to save the day.
Powers and Abilities
The plants display the same kinds of powers and abilities that they have in the video games: they shoot peas, punch, explode, freeze etc. The Pea Shooters and Melon-pults are capable of breaking open a metal fire hydrant upon repeated hits.
Generally speaking, they are usually able to rout the zombie army. Their weakness is that they need sun to operate. Crazy Dave has invented a sun machine that boosts their powers to higher levels and increases their size. The plants who naturally live in the time of the dinosaurs are naturally huge, and are able to eat zombie dinosaurs.