Catherine Periwinkle, affectionately known as Catherine-chan, is a milk rabbit and the eldest sibling in the Periwinkle family. Her lifelong passion for flowers, beginning in childhood, directly shaped her career path. She possesses a specific talent for selecting precisely appropriate flowers and colors tailored to different occasions, from birthdays to weddings. This floral expertise led her to co-found and operate Blooming Flower Shop in town alongside her close friend from college, Miranda Maple, forming their professional foundation within the Sylvanian community. Her introduction in 2018 redefined the Periwinkle family structure, establishing her as the older sister of Rebecca Periwinkle and repositioning her as a previously existing but newly acknowledged family member within the franchise's continuity.