Dianthera americana (dy-AN-ther-ah ah-mer-i-CAH-nah)
Family: AcanthaceaeNativeHerbaceous (3-15 ft)
Herbaceous (3-15 ft)Native
Water Willow is a herbaceous, aquatic perennial with white and purple flowers blooming from early summer into the fall. Only a few flowers bloom at the same time. The flowers are showy and bloom over a long period. It has green, 2-6" long willow-like leaves. Grow in full or partial sun, in shallow standing water up to 3', or moist soil that is sandy, muddy, or gravelly. It can be found in the shallow water of ponds, streams, lakes, and rivers. Water Willow spreads by underground stems to form large colonies. In shallow-water it provides refuge for young freshwater fish. The flowers are pollinated by bees, wasp flies, small butterflies, and skippers. Despite the common name, Water Willow is not a woody plant or related to the willows.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; High Organic Matter; Loam (Silt); Sand; Shallow Rocky
Soil drainage
Frequent Standing Water | Moist | Occasionally Wet
Available space
12 inches-3 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 2 ft. 0 in. - 4 ft. 0 in. | Width: 1 ft. 6 in. - 2 ft. 0 in.
Growth rate
Medium
Maintenance
Medium
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Erect; Mounding
Texture
Fine
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Opposite
Leaf shape
Elliptical; Lanceolate; Linear
Leaf margin
Crenate; Entire; Undulate
Leaf feel
Leathery; Rubbery
Leaf size
3-6 inches long, < 1 inch wide
Hairs present
No
Leaf detail
The medium green deciduous leaves are narrow in shape and smooth along the margins. 2-6" long and 1/4-1" wide.
Flower color
Purple/Lavender; White
Flower value
Long Bloom Season; Showy
Flower form
Head; Spike
Flower shape
Tubular
Flower size
< 1 inch
Flower detail
The flowers of Water Willow are mostly white with pale purple or lightly speckled with purple dots, and dark purple mottling at the base of the lower lobe.
Bloom time
Fall; Spring; Summer
Fruit color
Brown/Copper
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Dry and splits open when ripe to release 4 seeds
Stem color
Green
Wildlife & Ecology
Native status
Native
Origin
E. Canada to Mexico (Chihuahua, Coahuila)
Distribution
East Canada to Mexico
Wildlife value
Attracts bees, butterflies and wasps. Birds will eat the seeds