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American Water-willow Dianthera americana

Other Common Name(s):

Previously known as:

  • Justicia americana
Description

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.

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#purple#showy flowers#deciduous#water garden#perennials#white flowers#wetlands#standing water#moist soil#herbaceous#bicolor#pond#colonies#aquatic plant#wildflower garden#wet soils tolerant#bee friendly#bog gardens
 
Cultivars / Varieties:
Tags:
#purple#showy flowers#deciduous#water garden#perennials#white flowers#wetlands#standing water#moist soil#herbaceous#bicolor#pond#colonies#aquatic plant#wildflower garden#wet soils tolerant#bee friendly#bog gardens
  • Attributes:
    Genus:
    Dianthera
    Species:
    americana
    Family:
    Acanthaceae
    Life Cycle:
    Perennial
    Recommended Propagation Strategy:
    Division
    Root Cutting
    Country Or Region Of Origin:
    E. Canada to Mexico (Chihuahua, Coahuila)
    Distribution:
    East Canada to Mexico
    Play Value:
    Attractive Flowers
    Attracts Pollinators
    Colorful
    Easy to Grow
    Wildlife Cover/Habitat
    Wildlife Food Source
    Dimensions:
    Height: 2 ft. 0 in. - 4 ft. 0 in.
    Width: 1 ft. 6 in. - 2 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Herbaceous Perennial
    Perennial
    Water Plant
    Wildflower
    Habit/Form:
    Erect
    Mounding
    Growth Rate:
    Medium
    Maintenance:
    Medium
    Texture:
    Fine
  • Cultural Conditions:
    Light:
    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 To Plant:
    12 inches-3 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    3a, 3b, 4a, 4b, 5b, 5a, 6b, 6a, 7b, 7a, 8b, 8a, 9a, 9b, 10b, 10a
  • Fruit:
    Fruit Color:
    Brown/Copper
    Display/Harvest Time:
    Fall
    Fruit Type:
    Capsule
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    Dry and splits open when ripe to release 4 seeds
  • Flowers:
    Flower Color:
    Purple/Lavender
    White
    Flower Inflorescence:
    Head
    Spike
    Flower Value To Gardener:
    Long Bloom Season
    Showy
    Flower Bloom Time:
    Fall
    Spring
    Summer
    Flower Shape:
    Tubular
    Flower Size:
    < 1 inch
    Flower Description:
    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.
  • Leaves:
    Leaf Color:
    Green
    Leaf Feel:
    Leathery
    Rubbery
    Leaf Type:
    Simple
    Leaf Arrangement:
    Opposite
    Leaf Shape:
    Elliptical
    Lanceolate
    Linear
    Leaf Margin:
    Crenate
    Entire
    Undulate
    Hairs Present:
    No
    Leaf Length:
    3-6 inches
    Leaf Width:
    < 1 inch
    Leaf Description:
    The medium green deciduous leaves are narrow in shape and smooth along the margins. 2-6" long and 1/4-1" wide.
  • Stem:
    Stem Color:
    Green
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Angular
    Stem Form:
    Straight
  • Landscape:
    Landscape Location:
    Coastal
    Pond
    Riparian
    Small Space
    Landscape Theme:
    Native Garden
    Pollinator Garden
    Rain Garden
    Water Garden
    Design Feature:
    Mass Planting
    Small groups
    Attracts:
    Bees
    Butterflies
    Pollinators
    Specialized Bees
    Resistance To Challenges:
    Wet Soil