Invasive Alien Plants

The Problem

Invading alien plants (IAPs) are the single biggest threat to plant and animal biodiversity. IAPs have become established in over 10 million hectares of land in South Africa. The cost of controlling IAPs in South Africa is estimated at R600 million a year over 20 years. If IAPs are left uncontrolled, the problem will double within 15 years. IAPs waste 7% of our water resources; 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.

(Source DWAF website)

Legislation

In brief the Legislation states:

Category 1 plants should be removed and destroyed immediately

Category 2 plants may only grown with a permit for commercial reasons if not they must be removed.

Category 3 plants are permitted to grow where they already exist but no propagating or new planting is allowed.

For full details of the Legislation click here. For a full list IAP’s click here

For methods of removing Invasive Alien Plants go to control and weedbuster:

Invasive Alien Plants in the Drumblade Conservancy (updated 24th July 2009)

In the Drumblade Conservancy the following plants have been identified as being particularly problematic.  (Botanical name in brackets)

Category 1.  These plants should be removed and destroyed immediately.  You could be liable for a fine if they are found on your property

Black Locust (Robinia Pseudoacacia) The purple version is not common in our area, very pretty with
a lovely scent, but what a pest!  A single tree can soon become a thorny forest if not kept in check
 

Bugweed (Solanum mauritianum) Birds love the fruit and spread the seed far and wide

 
Black Wattle (Acacia mearnsii) Fire causes the Black Wattle to pop its seed pods.

 

Silver Wattle (Acacia dealbata) reproduces by both seed and root-suckers

Moth Catcher (Araujia sericifera).  The waxy flowers of this vine are very pretty

Watch out for jointed cacti - as a general rule they should all be removed

Mission Pricklypear (Opuntia ficus-india) & Jointed Cactus (Opuntia aurantica)

 
Imbricate (Opuntia imbricata) & Rosea Cactus (Opuntia rosea)

Category 2 plants may only grown with a permit for commercial reasons.  If you do not have a permit they must be removed or you will also be liable for a fine

White Poplar (Populus alba) particularly invasive on wetlands

   

Beefwood (Casuarina cunninghamiana) and Honey Locust seed pods and tree (Gleditsia tricanthos)

The following plants (Category 3) can be problematic but don’t remove your favourite shade tree or hedge, just watch out for them seeding on your property and remove the young plants immediately.

Common firethorn (Pyracantha angustifolia)

Common privet (Ligustrum vulgare)

Syringea (Melia azedarach) and Morning Glory (Ipomea pupurea)

Indigenous trees that would naturally be found within a 5km radius of the Drumblade area.  (the list includes woody shrubs and climbers).

* = easy to grow

African Wattle (Peltophorum africamum) - the frost is hard on young trees.

Bladder-Nut (Diospyros whyteama) - needs shade

Buffalo Thron (Ziziphus mucronata)

Cheesewood (Pittosporum viridiflorum) - needs shade

Common Hook Thorn (Acacia caffra) - grows easily if from local stock

Common Taaibos (Rhus pyroides) - very hardy (pioneer tree)

Cross-Berry (Grewia occidentalis)

Dogwood (Rhamnus prinoides) *

False Olive (Buddleja saligna)

Kiepersol (Cassonia ...)

Karee (Rhus Lancea) *

Mountain Karee (Rhus leptodictya) *

Ouhout (Leucosidea sericea)

Parsley Tree (hippobromus paucifloris)

Pompon Tree (Dais cotinifolia) *

Puzzle Bush (Ehretia rigida) - very slow growing

River Bushwillow (Combretum erythrophyllum) *

Sagwood (Buddleja salvifolia) *

Sweet Thorn (Acacia Karroo) *

Transvaal Bluebush (Diospyros lycioides) - difficult to find and very slow growing

Umbrella Thorn (Acacia tortilis)

White Stinkwood (Celtis Africana) - make sure you buy the genuine article, not the Australian or Asian species which become invasive. The indigenous White Stinkwood has a drooping stance and the leaves are hairy and the leaves are dark green. NB not shiny.

Wild Olive (Olea europaea subsp. Africana) *

Wild Peach (Kiggelaria Africana) - can be a bit frost tender

Wild Pear (Dombeya rotundifolia) - can be a bit frost tender

The following indigenous trees should grow if you can find a specimen that was profligated in a cold part of the country.

Brandybush (Grewia flava) - difficult to find

Camel Thorn (Acacia erioloba)

Camphor Bush (Tarchonanthus camphorates) - difficult to find

Cape Chestnut (Calodendrum capense)

Common Coral Tree (Erythrina lysistemon)

Common Rothmannia (Rothmannia capensis) - don’t plant in clay soil

Cork Bush (Mundulea sericea)

Jacket Plum (Pappea capensis)

Kooboo-Berry (Cassine aethiopica)

Lemon Thorn (Cassinapsis ilicifolia)

Mountain Hard Pear (Olinia emarginata)

Highveld Protea (Protea caffra) - likes well drained southern slope of hill, commonly known as the Suikerbos

Red Bushwillow (Combretum apiculatum)

Red Ivory (Berchemia Zeyheri)

Red-Leaved Rock Fig (ficus ingens)

Shepherd’s Tree (Boscia albitrunca)

Sickle Bush (Dichrostachys cinerea)

Small Knobwood (Zanthoxylum capense)

Transvaal Red-Milkwood (Mimusops zeyheri)

Tree Fuchsia (Halleria lucida)

Wild Medlar (Vangueria infausta)

The following are SA indigenous but not locally indigenous

Acacia Abyssinica

Breede River Yellowwood (Podcarpus elongates)

Cape Honeysuckle (Tecomaria capensis) - climber, needs a sheltered spot

Cape willow (Salix mucronata)

Freylina lanceolata

Outeniqua Yellowwood (Podcarpus falcatus)

Henkel’s Yellowwood (Podcarpus henkelli)

Pride of the Kaap (Bauhinia galpinii)

Real Yellowwood (Podcarpus latifolius)

Transvaal Gardenia (Gardenia volkensii) - needs a sheltered spot

Tree Wisteria (Bolasanthus speciosus) - needs a shelter when young, looks like a Jacaranda when in flower

Weeping Boer-Bean - needs a sheltered spot and very slow growing

White Karee (Rhus pendulina)