City warns exotic Tree of Heaven not welcome


It might look exotic and pretty, but the tree of heaven is considered an extremely harmful invasive species. To date, the City has almost 200 records of the tree of heaven (Ailanthus altissima) in Cape Town and urges members of the public to report any sightings of this tree.

While the southern suburbs have the highest number of records of this invasive species, the tree has also been reported to be growing in other areas, which proves that the tree of heaven has already invaded suburbs across the city.

The City of Cape Town noted that “the rapid growth and aggressive root system of this species poses a threat to urban infrastructure.

Capable of growing through cracks in sidewalks, gutters and walls, and penetrating underground pipelines, this plant can cause significant damage to infrastructure.

Mayco member for energy, environmental and spatial planning, Johan van der Merwe said, “Residents should therefore not hesitate to report sightings to the City so that we can step in and limit the damage caused.”

Popular as an ornamental tree, this deciduous tree emanates from mainland China and occurs mostly in urban environments where it quickly spreads into disturbed sites, degraded fields and along roadsides.

Vigorous growth, coupled with the plant’s ability to produce a chemical from its roots known as ailanthone which prevents the growth of other plant species, may result in drastic alterations to natural habitats, according to the City.

“A case has been reported where the root system of a tree of heaven growing on an adjacent property spread far enough to crush the boundary wall and crack the lining of the neighbour’s swimming pool,” said Mr Van der Merwe.

Physical contact with the tree, particularly with the leaves, can lead to skin irritation and, if left untreated, can cause severe itchiness and a persistent rash resulting in high levels of pain and discomfort. In this instance, medical attention may be required to reduce these effects. This invasive species has been classified under the National Environmental Management Biodiversity Act as Category 1b, meaning that it must be controlled, or removed and destroyed.

* Residents who want to report invasive species, or more information can visit or on

* Cape Town residents are asked to report sightings of this plant to the City’s Green Jobs Unit: