Red water fern
Common name:Red water fern
Scientific name:Azolla filiculoides (Azollaceae)
Alternative common names:
A free-floating perennial aquatic fern from tropical South American with horizontal stems up to 35mm long. It has a loose branching pattern. The leaves are 1-1,5mm long, almost circular in shape and are silvery-green turning reddish brown or purple in winter.
Where does this species come from?Tropical South America.
What is its invasive status in South Africa?Existing legislation: CARA 2002 – Category 1 NEMBA – Category 1b
Where in South Africa is it a problem?This water weed is a problem throughout most wetlands in South Africa.
How does it spread?Spores and detached plant segments.
Why is it a problem?It can rapidly cover an open water surface and severely degrade aquatic ecosystems. These dense mats of red fern reduce light penetration and causes de-oxygenation, having a significant affect on organisms living below the water surface. This results in reduced quality of drinking water caused by bad odour, colour and turbidity.
What does it look like?General description: A floating tiny-leafed aquatic plant which forms dense mats on the water surface, often turning red in colour. Bark: None. Leaves: Minute silvery-green leaves turning reddish brown or purple in winter. Flowers: None Fruit/seeds: Fruiting bodies are minute, and appear in October to February.
Does the plant have any uses?Used mostly as an aquarium plant and sometimes as a water feature ornamental.
Plant me instead alternatives
Cape pond weed (Aponogeton distachyos), small yellow water lily (Nymphoides thunbergiana).