The Plant Chronicles: Chapter 1: Cactus and Blover
Cactus was a prickly plant that can shoot air and ground stuff, but this a quite different story. Cactus as a child, had an incident. In a festival where balloons are lifted along with heavy stuff until a foolish plant called Blover blew a balloon until it hits a post and it's heavy item falls onto Cactus and then Blover and his family are shunned and banned from the festival for 2 decades.
Months after the incident, she finally had a phobia of balloons which made her decide to never go to the park till the end of time. 10 years later, her friends finally had enough and made a plan to meet with Blover. Blover was a former childhood friend until that fateful incident, he says that he'll never meet her ever again.
Plantern, Blover's only friend was also part of the meeting.
As a child, his old house was burned down due to his family's carelessness so they now live in an apartment where Cactus also lives. Him and his family are evicted out because of the balloon incident. 5 years later, he became a fireman after remembering the fire. He quitted the job to pursue the dream of selling balloons, then another 5 years he became a storm chaser/meteorologist working for the local media of the plant society's weather reports.
His family prevented him from meeting Cactus' friends because they might remember that incident, so he lets his only friend, Plantern to do the thing instead.
The two finally met and became the best of friends no matter what their families say, and they team up when the zombies finally attacked.