This plant is amphibious, as suggested by the species name. Stems may creep, float or grow erect, rooting at nodes that come in contact with moist substrate. Stems are known to reach 3 m in aquatic plants and are stout. Leaves are lanceolate, ovate, arrow-shaped or lance-oblong, usually 2-15 cm, but can be ›30 cm. Flowers are in dense, terminal spikes (1-15 cm long) of many five-lobed, pink, rose or red flowers. Sheaths (ocrea) are brown or tan, up to 5 cm, have no cilia and may be leaf-like distally.
In ponds, marginal stands can expand noticeably during the summer, both upslope onto the land, and into deeper water. If water levels drop, aquatic plants become terrestrial without missing a beat.
Photographs by Cliff Halverson