Virginia Iris

Iris virginica, southern blue flag, is a clumping perennial iris native from eastern Canada through the central and eastern United States, growing in shallow water and saturated ground. Blue to violet flowers with distinctive gold and white signal patches open in late spring on stems one to two and a half feet tall. Strap-like leaves arch outward and often lean into the water.

It grows happily in standing water, which sets it apart from garden irises that rot in the same conditions, and its rhizomes knit together to hold soft pond margins. The rhizomes are toxic if eaten, and deer avoid the plant almost entirely — a rare combination of pond-edge reliability and browse resistance.