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German wasp | Vespula germanica

German wasp

Vespula germanica

Coral bush | Ardisia crenata

Coral bush

Ardisia crenata

Purple loosestrife | Lythrum salicaria

Purple loosestrife

Lythrum salicaria

Pom pom weed | Campuloclinium macrocephalum

Pom pom weed

Campuloclinium macrocephalum

Canarybird bush | Crotalaria agatiflora

Canarybird bush

Crotalaria agatiflora

Peanut butter cassia | Senna didymobotrya

Peanut butter cassia

Senna didymobotrya

Rubber vine | Cryptostegia grandiflora

Rubber vine

Cryptostegia grandiflora

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Environmental Programmes

In order to tackle our country’s socio-economic challenges, the government adopted the Outcomes based approach to improve government performance and providing focus on service delivery. find out more

Red water fern

Azolla filiculoides

Common name:

Red water fern

Scientific name:

Azolla filiculoides (Azollaceae)

Alternative common names:

Watervaring (Afrikaans)

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. 

Additional Info

  • 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).

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General News Updates

2019 National Symposium on Biological Invasio…


This is your invitation to South Africa's 2019 National Symposium on Biological Invasions. The convention is hosted by the Centre for Invasion Biology (CIB), University of Stellenbosch, and the Biolo... Read more

2019 Invasive Species Training


During the past five years (2014-2018), ISSA invasive species trainers have trained 4 000 in the identification of invasive species and laws pertaining to invasive species across South Africa.  ... Read more

Alien Grass Working Group


Who are we? The South African National Alien Grass Working Group was jointly initiated by the South African Biodiversity Institute (SANBI) and the Centre for Excellence in Invasion Biology (C·I·B) in... Read more

Permits for planting indigenous Cynodon?


On 16 February, 2018, South Africa's Department of Environmental Affairs issued amendments to the regulations and lists relating to the National List of Invasive Species.  Updates to the draft&n... Read more

Invasive species training 2018 dates released


Interested in invasive species?  How much do you know about NEMBA invasive species compliance for landowners and organs of state? The South African Green Industries Council (SAGIC) have released... Read more

Communications post for Africa advertised


The Nature Conservancy has advertised a brand new post:  Communications Manager, Africa Region. Knowledge of invasive species and water would be an asset in this post. See details below:    Job Titl... Read more