There has been much talk about the legislation around Alien and Invasive Species of late.  Here in Modderfontein we are fortunate enough to live in a space where we get to experience beautiful fauna and flora in our estate as well as the surrounding conservation areas.

The legislation is in place to protect our country’s bio-diversity, our natural resources such as grasslands, wetlands, water catchment areas as well as farmland, where our food security is paramount.  Most of us are not aware of the devastating effect some alien invasives, such as water hyacinth has on our water resources.  Not only that, there are weeds and trees that cause the soil to become barren, rendering farmland completely unproductive and therefore displacing thousands of rural subsistence farmers.

Legislation under the National Environmental Management: Biodiversity Act, 2004, specifies a list of alien invasive species around the country.  This list is ever-changing according to how biodiversity is managed by the Department of Environmental Affairs. For the latest list and classification on what action is appropriate, please refer to We will post this link on the THOA website for ease of reference.

Here in Thornhill the responsibility of managing alien invasives is collective.  The trees on our pavements are the responsibility of Johannesburg City Parks and our local municipality.  The watercourse area is currently the responsibility of the Johannesburg Roads Agency and our parks and public areas are our collective responsibility, managed by the THOA Gardens Committee.  Each resident is responsible for their individual properties and although legislation is still relatively new and untested, there is a duty of care to remove alien invasive plants to protect our larger environment.  Legislation also dictates that property owners should have a clearance certificate prior to selling their property, but it seems as if this is not currently enforced.  In order to avoid future liability, it is advisable that you ensure compliance where necessary in your own garden.  We will attend to compliance in common areas.

The current list of alien invasives will guide you on what action is appropriate.  It is not necessary to remove all of the listed species as they are categorised according to the threat they pose.  Some should be removed immediately if you have it in your garden where others can be left to naturally die off.

For further information on current legislation, please refer to the Department of Environmental Affairs or the website listed above.

Janita Janssen for the THOA Gardens Committee