I. pseudacorus grows best in very wet conditions, and is common in wetlands, where it tolerates submersion, low pH, and anoxic soils.

While it is primarily an aquatic or marginal plant, the rhizomes can survive prolonged dry conditions.

Large I. pseudacorus stands in western Scotland form a very important feeding and breeding habitat for the endangered corncrake.

However, when number of flowers per floral unit, flower abundance, and phenology were taken into account, it dropped out of the top 10 for most nectar per unit cover per year, as did all plants that placed in the top ten, with the exception of common comfrey, Symphytum officinale.

[11] According to Pierre Augustin Boissier de Sauvages, an 18th-century French naturalist and lexicographer, the name fleur-de-lis applied to the heraldic symbol may be related to Iris pseudacorus rather than to a lily, based on the shape and yellow colour of the flower.