"She finally decided, 'f––– it. I'm going to do what I want to do and I don't care what people think," a friend of Perry tells PEOPLE. "Her hair is an outward statement of her freedom."
The source says that Perry, 29, feels that her relationships with Russell Brand and John Mayer have been toxic.
"Katy will not let romance derail her life right now," says the source, who adds that Perry has not responded to recent texts and calls from Mayer.
"She is happy being single. I don't see her getting into another relationship for a very long time. Why would she? She has a fantastic career, a ton of friends and is generally happy with things. She thinks that a relationship will complicate things right now."
Instead of looking for love, Perry is busy focusing on her career – and spending long days getting ready for a world tour that begins on May 8.
"She's looking for something showstopping [for her tour]," says the friend. "Something that will grab the attention of everyone. She can't focus on that if she's dating someone. Right now, she needs to have a one-track mind, and it can't be about a boyfriend."
"Katy has always been a romantic," continues the source, "but she knows that it doesn't all have to happen immediately. She doesn't need to have the prince on the white horse now. She'll wait, and take care of herself in the meantime."
And part of that waiting may include more fashion statements.
"She's so thrilled about the hair," says the friend. "She loves how it came out. This is the time in her life where she can do whatever she wants. Today, it's green hair. Tomorrow, it may be purple. No one is going to tell her 'No.' "