Botanical name: Butomus umbellatus
Common name: Flowering Rush
Family: Butomaceae
Origin: Europe, Asia
USDA Plant Hardiness Zone Map
It is sometimes known as the Water Gladiolus because of the attractive bi-colored flowers, 2.5cm (1in) across and gathered in a distinctive umbel at the top of stems which are taller than the long, narrow leaves.
Link to this plant:
https://toptropicals.com/catalog/uid/butomus_umbellatus.htm