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Water Velvet Azolla caroliniana

Phonetic Spelling
a-ZOL-luh kair-oh-lin-ee-AN-uh
Description

Eastern mosquito fern is a native annual aquatic fern in the Salviniaceae family.  This very short plant grows less than 1 inch tall but can break off and form a mat that covers available surface water very quickly making it difficult for mosquitos to deposit their eggs, hence the common name "mosquito fern". 

Growing in still or very slow moving water it naturalizes in shallow ponds, ditches, and sluggish streams. The delicate lacey scale like leaves overlap and float above the surface forming a dense mat with the roots trailing in the water.  New leaves are a bright or gray green and can fade to rusty red especially if grown in really bright conditions.  To propagate this plant move sections of it to a new area.  To keep it alive when temperatures dip, overwinter indoors.

The leaflets house a symbiotic blue-green alga (Anabaena azollae) that fixes nitrogen.  Use it in water gardens, ponds, or aquariums though the leaves are normally not eaten by fish.

Insects, Diseases, and Other Plant Problems:  No serious problems.  

 

 

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#full sun tolerant#water garden#heat tolerant#annuals#red leaves#piedmont#spores#fern#wetlands#stream banks#food source wildlife#NC native#spreading#ponds#native garden#ditches#mountains#summer interest#water plant#native annual#native water plant#fruits summer#forb#food source herbage#wet soils tolerant#fruits#waterfowl#wetland margins#partial shade tolerant#Audubon#tiny leaves#coastal plant#partial sun tolerant
 
Cultivars / Varieties:
Tags:
#full sun tolerant#water garden#heat tolerant#annuals#red leaves#piedmont#spores#fern#wetlands#stream banks#food source wildlife#NC native#spreading#ponds#native garden#ditches#mountains#summer interest#water plant#native annual#native water plant#fruits summer#forb#food source herbage#wet soils tolerant#fruits#waterfowl#wetland margins#partial shade tolerant#Audubon#tiny leaves#coastal plant#partial sun tolerant
  • Attributes:
    Genus:
    Azolla
    Species:
    caroliniana
    Family:
    Salviniaceae
    Uses (Ethnobotany):
    Grown in rice paddies as a green fertilizer or used as animal feed. It is being studied as a biofuel and has been used for pollution mitigation.
    Life Cycle:
    Annual
    Recommended Propagation Strategy:
    Division
    Stem Cutting
    Country Or Region Of Origin:
    Americas
    Wildlife Value:
    This plant benefits waterfowl and shorebirds.
    Play Value:
    Wildlife Cover/Habitat
  • Whole Plant Traits:
    Plant Type:
    Annual
    Fern
    Native Plant
    Water Plant
    Habit/Form:
    Spreading
    Growth Rate:
    Rapid
    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 Drainage:
    Frequent Standing Water
    Occasionally Wet
    Available Space To Plant:
    Less than 12 inches
    NC Region:
    Coastal
    Piedmont
    USDA Plant Hardiness Zone:
    7a, 7b, 8b, 8a, 9a, 9b, 10a, 10b, 11b, 11a
  • Fruit:
    Display/Harvest Time:
    Summer
    Fruit Description:
    No fruits. Magaspores (female gameophytes) and microspores (male gametophyte) appear from June to September.
  • Flowers:
    Flower Description:
    No flowers.
  • Leaves:
    Leaf Color:
    Gray/Silver
    Green
    Red/Burgundy
    Deciduous Leaf Fall Color:
    Red/Burgundy
    Leaf Type:
    Fronds
    Leaf Margin:
    Lobed
    Hairs Present:
    Yes
    Leaf Length:
    < 1 inch
    Leaf Width:
    < 1 inch
    Leaf Description:
    Lacey, bright green to gray green fronds arranged in two rows of .5 mm long scale-like leaves with two lobes. The upper leaf is above the surface and the lower larger leaf floats below. On the upper lobe leaves have one celled hairs. Turn reddish in full sun and during fall.
  • Stem:
    Stem Is Aromatic:
    No
    Stem Description:
    Prostrate stems branch
  • Landscape:
    Landscape Location:
    Pond
    Landscape Theme:
    Water Garden
    Problems:
    Weedy