Azolla

Azolla is a nitrogen-harboring true fern and it will multiply its weight three times each week during the summer months.

Azolla Caroliniana is nonnative and on the federal noxious weed list and should not be grown.

Any type of this plant is not recommended to be grown if no ornamental fish are present.

Mosquito fern can be removed by raking or seining it from the pond's surface.

Azolla has several names Azolla Caroliniana or its more common names fairy moss or mosquito fern.

Azolla Caroliniana is a species of Azolla it is native to America, Argentina, and Uruguay. It is a freshwater plant aquatic fern, with scale-like frond 5-10mm long, green to reddish, most often reddish in strong light and in winter.

They are covered in fine hairs that give it the appearance of velvet. It is able to fix nitrogen from the air by means of symbiotic cyanobacteria. It can survive winter water temperatures of 5 degrees C with optimum summer growth between 25-30 degrees C.

Azolla is of commercial importance in cultivation in southern and eastern Asia as a bio-fertilizer, valued for its nitrogen-fixing ability, which benefits crops such as rice when the fern is grown under it and reduces the need for artificial fertilizer addition. The thick mat of fronds also suppresses pond algae.

Harvested fronds are also used as a food for fish and poultry. It is also often used as a floating plant in both cold water and tropical aquariums, as well as in outdoor goldfish ponds; it is propagated by division.

Azolla prefers slightly acidic water and can be collected and transferred during the spring or summer. It is best to place mosquito ferns in sheltered areas of the pond.