Water Fern, Ferny or Red Azolla

Azolla pinnata

Physical Characteristics

Azolla pinnata is an evergreen Fern at a fast rate. See above for USDA hardiness. It is hardy to UK zone 10. The plant is not self-fertile. It can fix Nitrogen. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid and very alkaline soils. It can grow in full shade (deep woodland) semi-shade (light woodland) or no shade. It prefers moist or wet soil and can grow in water.

Distribution

Widespread in tropical Africa and southeast Asia through to the Pacific including Australia, New Zealand.

Habitats

Edible Uses

None known

Medicinal Uses

None known

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[ 200 ]. Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase[ 172 ].