Comfey picks flowers and always carries them around. It makes a ring of blossoms and spreads oil from its body on it, which changes the flowers so they emit a soothing fragrance. It has a habit of giving these flower rings to those it’s fond of. The aroma can soothe both itself and its allies. Comfey also helps with the treatment of people and Pokémon at Pokémon Centers and hospitals, thanks to its aroma.
When attacked by other Pokémon, it throws its flowers at them to create an opening, and then it either flees or strikes back.
X-scizor is right.
Comfey is a fairy; it just carries flowers around.