There are four categories of problem plants in South Africa:
Category 1: Declared weeds.
These are prohibited on any land or water surface in South Africa and may not be planted or propagated.
Some are popular garden plants, but their harmfulness outweighs any useful properties they might have
and all attempts should be made toeradicate them. (Plants that are problematic in specific areas
may be declared weeds only in certain provinces, such as Metrisideros excelsa in the Western Cape
and Lantana camara in KZN and Mpumalanga.)
The legislation governing the trade or sale in invader plants falls under the Conservation of Agricultural Resources Act, or CARA (Act
Regulations 15 and 16, which concern problem plants,
CARA is administered by the Department of Agriculture, through its Directorate: Land Use and Soil Management. Reputable plant nurseries and garden centres should be aware of the latest regulations and should not trade in or stock prohibited or invasive plants or seeds.
Category 2: Declared invader plants with a value.
These plantshave the proven potential to become invasive but have beneficial properties that warrant their continued existence under controlled conditions. This includes plants used for purposes such as building material, animal fodder, soil stabilization or medicinal uses. They may be grown only with a permit and in demarcated areas, provided that steps are taken to prevent their spread into other areas.
Category 3: Ornamental plants.
These have the proven potential to become invasive. They may no longer be planted, but existing plants may remain in the garden, provided reasonable steps are taken to prevent them from spreading.
Category 4: Encroachers.
This category applies to landowners in rural areas only and is concerned with indigenous species that, under certain circumstances, may encroach on other vegetation, leading to bush densification.
Such encroachment must be prevented, or combated where it already occurs.