Plantain lilies are native to eastern Asia and about 20 types of Hosta can be found across Japan, producing pale pink flowers from June to August. Their young leaves and petioles are edible, used in various Japanese dishes such as salads, pickles, and miso soup.
The lily's Japanese name is "giboshi" or "giboshu," a type of ornamental finial used on Japanese railings (no English translation), after the shape of the lily's bud looking like the finial.