January is a time when invasions by 348 bad alien plants are at their worst. Now is the time to check your gardens to find out what plants have invaded your garden and to get rid of them.
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It is estimated that there are approximately 27 000 indigenous species in South Africa and 9 000 foreign plant species that have been introduced to the country over the past few centuries. Of these 9 000 exotic or alien introductions, 348 have been identified as ‘bad’, ecologically damaging, invader plants.
Legislation is currently in the works to address these 348 invader plants, but it will take months for the new laws to be passed. In the meantime, it is important to remember that regulations passed in 2001 under the Conservation of Agricultural Resources Act, 1983 (Act No 43 of 1983) identify198 of the worst invasive alien plant species as declared illegal weeds. Under this legislation, landowners are responsible for the removal and control of any of these 198 plants on their properties.
Categories of alien invasive plants
The existing law divides these 198 problem plants into three categories. Although gardeners are only obliged by law to remove and destroy Category 1 plants, eco-friendly gardeners are endeavouring to rid their gardens of any designated invader weeds plants identified as a danger to the country’s local ecosystems by environmentalists and weed scientists.
For example, if a designated weed, such as a syringa tree, is a feature in your garden, now is the time to plant a suitable ‘plant me instead’ alternative beside the syringa (such a an acacia, leopard tree, wild olive or tree wisteria) so that you will have a replacement feature when the time comes to remove the syringa. In the forthcoming proposed legislation, syringa trees have been moved to a category that indicates that they will have to be removed and destroyed.
As the law stands, there are three categories:
- Category 1
These IAPs may no longer be grown anywhere in South Africa. If they are in your garden, they should be removed and destroyed immediately. Trade in these plants is prohibited. - Category 2
Primarily plants of commercial value to forestry and agriculture, these IAPs must be removed from suburban gardens and can only be grown with a permit in public spaces such as parks, schools and hospitals. Permits are obtainable from regional offices of the National Department of Agriculture, Fisheries and Forestry. - Category 3
These IAPs are permitted to grow where they already exist. However, no propagating, new planting or trade is permitted. In other words, plants already growing in the garden may remain, but no more may be planted.
Why are IAPs a problem?
Invasive alien plants are highly adaptable, vigorous growers that easily invade a wide range of ecological niches. They:
- Have invaded and taken over 10% of the country. This is well over 10 million hectares of land (or an area the size of KwaZulu-Natal).
- Use 7% of the water resources in South Africa. This is roughly the same amount of water needed by humans to survive in this country.
- Threaten our rich biodiversity by replacing indigenous and endemic vegetation. This will result in a loss of insect species that are dependent on these plants and the ripple-effect loss of the birds, reptiles and mammals that feed on those insects.
- Invade land better used for crops and livestock grazing.
- Are often toxic to man or animals.
Action against invaders
Seedlings of many of these plant species appear in gardens all the time, courtesy of birds passing through. It is important to be able to identify them and pull them out as soon as possible to eliminate costly tree felling at a later stage. Get to know these plants and constantly be on the lookout for them. Always try and eliminate them before they mature and start to set seeds in your garden.
Another key factor in eradicating these plants is that the roots have to be eliminated to prevent the plants from re-growing. This can either be done mechanically by digging the root ball out or chemically by applying a tree and shrub killing chemical to the stump.
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