Small, free-floating, mat-forming, aquatic fern < 3 cm long. Plant is triangular, with a straight midsection and pinnately arranged side branches. Roots are feather-like with fine rootlets. Leaves are minute, alternate, overlapping and green/red. Sporocarps are round and formed on the undersides of leaves.
Although ferny azolla is not a legally declared pest plant, it may still be invasive in some situations. Consider lower risk alternatives for your garden, such as native plants.
Lakes, ponds, wetlands, ditches, dams, slow-moving waterways.
Spores produced. Vegetative spread from fragmentation. Spores and fragments dispersed by water, waterfowl and wind. Human-mediated dispersal through movement of contaminated boats, equipment and machinery.
Forms dense mats, displacing native aquatic plants and reducing oxygen levels.
Increasing shading over the waterway can reduce an infestation. Spraying aquatic weeds result in plants rotting in the water. This decreases dissolved oxygen in the water and in large amounts can kill aquatic life. Consider raking and only spraying regrowth in spring.
CAUTION: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.