Water willow

 Water-willow, Justicia americana,  is a common perennial along stream and lake margins.  It grows to 3 feet tall and often forms dense colonies that help stabilize shorelines.  The stems do not usually branch and have prominent whitish lines.  Leaves are opposite, long and narrowly tapered (up to inches 6 long and ½ inch wide) with smooth margins and a distinctive whitish mid-vein, looking much like those of the willow tree. 

Flowers bloom from May through October on long stems originating from the base of the leaves. The blooms are 5-petaled, orchid-like (3/4 inch diameter), white with purple/violet streaks on the lower petals.  Water-willow can spread from seeds and forms extensive rhizomes by which it forms colonies and spreads rapidly.

Submerged portions of all aquatic plants provide habitats for many micro and macro invertebrates.  These invertebrates in turn are used as food by fish and other wildlife species (e.g. amphibians, reptiles, ducks, etc.).  After aquatic plants die, their decomposition by bacteria and fungi provides food (called “detritus”) for many aquatic invertebrates.  Deer will browse the leaves while beaver, muskrat, and nutria will consume the rhizomes of water-willow.