Canna flaccida is aquatic species, with narrow, blue-green (glaucous) leaves, very pretty, large, lightly perfumed, canary yellow flowers growing in clusters at the tops of long stalks. The lip of the flower is wavy. Flowers emerge in the evening and wither in the heat of the following day, the only member of the genus that behaves in this manner, all others open early in the morning and are strong enough to survive at least one day. It grows as a marginal plant in up to about 15 cm of still or slow-moving water.