Scientific Name: Justicia americana
Common Name(s): Water Willow, American Water Willow

Photos by Kayla Sayre, Bella Vista POA Fisheries & Water Quality Sr. Technician

Identification:

American water willow is a native water-loving flower that grows along the shorelines of Bella Vista’s Lakes. Read until the end to understand more about identifying this beautiful native plant and the ecological benefits to both fish and pollinators!

American water willow is a water-loving herbaceous perennial plant. It is found in shallow water along shorelines. Water willow can range in height from three to five feet, with roots and stems below the water’s surface and the top quarter of the plant along with the flowers emerging out of water.
Flowers appear from June to September They are similar in appearance to an orchid, with each petal fusing at the base to form a tubular shape. Additionally, the flower has a landing strip in the form of a single petal that sticks out separately at the bottom of the flower, allowing for efficient pollination. Water willow is dioecious, meaning that male and female reproductive structures are on separate plants.

Although water willow bears the name “willow,” it does not share taxonomic lineage with the traditional willow trees in the willow family (Salicaceae). It was given the common name “water willow” because its leaves resemble those of the willow tree. The leaves are lanceolate in shape, being oblong with a pointed tip similar to the shape of a sword or lance. The leaf margins are smooth, and the leaves are 2 to 4”-inches long and ½-inch wide.

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Range:

American water willow is found in the eastern and central United States with a limited amount found in Arizona.

Water willow is in the family Acathaceae, which is composed of herbs, shrubs, and small trees. This family contains around 2500 species worldwide, with most members of this family found in the tropics. Only a few members of this family are cold hardy and found in the United States.

Ecology:

Water willow is an emergent aquatic plant, where the top half of the plant emerges from water habitats. It prefers habitats with water that is up to three feet in depth. It will not grow without consistent soil moisture and does best in shallow water that is still or slow moving. It does well on sand-, gravel-, and mud-bars in rivers and ponds and thrives along the shoreline of lake habitats and wetlands. Water willow can live in partial to full sunlight but does best in full sun where it receives six or more hours of direct sunlight.

Water willow provides good nursery habitat for gamefish. It can form thick vegetation stands that extend along shorelines. Young fish use this aquatic vegetation to hide from larger fish while they are small and still in their nursery phase.

Stands of water willow also offer shoreline protection and stabilization in Bella Vista lakes. The extensive rhizomial network, along with the plant’s emerging portion, provides excellent shoreline protection from wave action generated by wind or boats. This buffer acts as a shock absorber protecting shorelines against erosion. Water willow stands are crucial for protecting shorelines that do not have a man-made seawalls.

Water willow attracts most pollinators but is especially adept at attracting native bees, such as bumble bees, because of its color and shape. The tubular, orchid-like shape of water willow is ideal for holding pollen and nectar. A single petal sticks out at the bottom of the flower, acting as a landing strip for bees and other pollinators. Additionally, the flower has pollinator guidelines in the middle of its petals, which are blue to purple. This is especially attractive to bees since they are adept at seeing the blue portion of the UV color spectrum. Along with pollination and reseeding, water willow also grows from rhizomes. Rhizomes are roots that extend from the primary plant and grow into open spaces where new water willow shoots can emerge.

Special Notes:

In Bella Vista, we at the Lakes Ecology Lab love water willow. It is currently the dominant aquatic plant in Bella Vista lakes serving as much needed habitat for young fish. Water willow also provides natural shoreline protection against wave action from wind and boat wakes. We want to encourage lakefront property owners to tolerate as much water willow around the shoreline as possible without impeding recreational enjoyment of the lakes.