Bog Bean (Menyanthes trifoliata)
A favorite hardy bog plant is the Bog Bean. It has large, three leaves that are veined. The foliage forms a creeping rhizome that floats out onto the water. The flowers are pink clusters that open to white, star-shaped blooms that are highly fragrant. The flowers will appear late April through July whereas the foliage will appear lush throughout the whole season. The flower stalks will stand 2-6 inches high above the leaves which are about 3 inches high. It does best if planted in 1 - 3 inches of water and will then creep out onto your water surface, extending 3' to 5'. It prefers full sun to part shade and is hardy in zones 2-7 and should be kept in the water throughout the winter even if it freezes.
Buy Bog Bean, Hardy Bog Plant, here.