From PinataIsland.info, the Viva Piñata wiki
Petunia may appear soft-spoken and well-mannered, but buried beneath that quiet exterior is a karate-chopping, kung-fu-fighting thrill seeker. Since arriving on Piñata Island from the Land of the Rising Sun, Petunia’s daredevil-may-care antics have made quite an impression, good and bad. Some, like Paulie, find her aggressive streak a little intimidating, while others, like BFF Hailey Horstachio, appreciate her live-in-the-moment attitude towards life. Ultra-competitive and always up for a new challenge, Petunia can’t wait to test her skills in the competition, score a big victory, and hopefully score some one-on-one time with a certain brainy Pretztail. She is Japanese and speaks steriotypical engrish.