Life is a Garden | South Africa |

All you need to know about invasive Alien Plants.

1. What are invasive alien plants?

WeedBuster Week is an annual event in South Africa which runs from 5-11 October this year. Its aim is to let everyone know what invasive alien plants are, the extent of the problems they cause and how we can combat them.

Why are we holding WeedBuster Week?
Invading alien plants (IAPs) are the single biggest threat to plant and animal biodiversity in South Africa. The cost of controlling IAPs in South Africa is estimated at R600 million a year over the next 20 years.

Did you know?

Alien invasive plants (IAPs) have invaded 10 million hectares of South Africa or an area the size of KwaZulu-Natal). This is 10% of our available land. Invasive alien plants in South Africa use 7% of our water...which is about the same amount of water needed by humans to survive in SA.

IAPs cause major damage to ecosystems by crowding out key species and thereby threaten the biodiversity which attracts tourists to our country. IAPs also reduce our ability to farm; intensify flooding and fires; cause erosion, destruction of rivers, siltation of dams and estuaries, and poor water quality and can cause a mass extinction of indigenous plants and animals. Aquatic invaders cover dams and lakes and block rivers. If IAPs are left uncontrolled, the problem will double within 15 years.

What is an invasive alien plant (IAP)?

There are 27 000 indigenous plant species in the country and 9000 exotic or alien species in South Africa (ie plants that came from foreign lands).Only 198 of the 9000 foreign plant species in South Africa are deemed to be problem invader aliens - or ‘bad' plants.

IAPs are plants that have been introduced from other countries and out-compete the indigenous species. They are highly adaptable and don't have the natural enemies they would have back home. They easily invade many ecological niches in their new homes, from rivers to mountain kloofs.

They grow fast and produce enormous amounts of seed. Or they have deep or spreading root systems that are difficult to remove. This helps them to multiply quickly and crowd out local plants. Because of the way they grow, and if we do nothing about the spread of IAPs, the land they occupy could double in the next 15 years.

What are some of the culprits? Their common names are wattle, lantana, bugweed, pampas grass, syringa, Port Jackson, rooikrans and gum trees. In the water, invader aquatics include water hyacinth, water lettuce and parrot's feather. These trees are commonly seen in gardens and in the veld and therein lies the problem.