Conservation

For up-to-date news, activities and calendar of events please visit www.crocodileriverreserve.co.za  

This biodiversity stewardship project aims to provide formal conservation protection for the area of the Rhenosterspruit Nature Conservancy, and beyond. 

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Guide to Invader Species - Weeds

December is here, and so are the bright splashes of pink in the veld as the dreaded pom pom flowers.

Pom pom is one of the classified alien invaders that MUST be removed by law. You can - and will - be fined if you take no action against Category One Invaders.

This article explains more about herbicides, classified aliens and your responsibilities.

Invasive species are a concern in all biomes and ecosystems across South Africa, with 180 species of invasive alien plants already infesting the equivalent of 10 million ha, or 8% of South Africa’s surface area."

~ SOUTH AFRICA’S NATIONAL BIODIVERSITY STRATEGY AND ACTION PLAN COUNTRY STUD

 

Defining Weeds

'Weeds' generally refers to plants that grow where they are not wanted. Many indigenous pioneering species are weeds of disturbed sites such as roadsides, overgrazed land and waste places. Alien weeds occur in the same disturbed sites and are also common in cultivated lands, planted pastures and lawns. 'Environmental weeds' are alien plants that invade natural vegetation.

'Invasive plants', 'plant invaders' or 'invader plants' usually refers to alien plants that are capable of reproducing and spreading without the direct assistance of humans. The most aggressive invaders can spread far from parent plants and cover large areas.

In South Africa the term 'invasive' has sometimes been applied to indigenous species whose distribution or density has increased in response to man-induced changes in the environment. Indigenous woody species that invade overgrazed land are referred to as 'bush encroachers'.

Impact of invaders

Invasive alien plants threaten indigenous vegetation and consequently, biodiversity. The invaders use valuable and limited water resources. Most of the invaders require more water than the indigenous vegetation, and are depleting the valuable underground water resources. Many invasive plants are also responsible for causing exceptionally hot fires. Invaders also affect the makeup of soil structure - the pom pom weed for instance releases a chemical into the ground which prevents other plants from thriving in its vicinity.

Invasive Plants

Some weeds therefore have a far greater impact on the environment, destroying biodiversity and valuable grazing as they spread. The City of Tshwane has earmarked the invaders most prevalent in this area from the 180 nationally flagged invaders.

The weeds are classified, and within that classification the action that can be taken against a negligent land owner is prescribed.

Category 1: Declared weeds

These are plants that must be controlled (removed) on land or water surfaces by all land users. These plants may no longer be planted or propagated and all trade in their seeds, cuttings or any other propagation material is prohibited.

Category 1 plants include:
Lantana - Pom pom weed - Bugweed - Azolla - Queen of the night - Pampas grass - Cat`s claw creeper - Red sesbania - Yellow oleander - Yellow bells - Water hyacinth

Category 2: Declared invaders (plants with commercial value)

These are invader plants that pose a threat to the environment but nevertheless can be exploited for timber, fruits, fuel wood, medicinal plants, animal fodder, building material or shelter of to stabilise soil. These species are only allowed to occur in demarcated areas. If the plants are used for commercial purposes, landusers have to obtain a water use licence as these plants consume large volumes of water. Where plants occur outside demarcated areas they have to be removed.

Category 2 plants include:
Black wattle - Patula pine - Sisal - Red eye - Grey poplar - Watercress - Port Jackson willow - Guava - Cluster pine - Honey locust - Weeping willow (not to be confused with the indigenous willow)

Category 3: Declared invaders (plants with ornamental value)

These are plants that have the potential of becoming invasive but are considered to have ornamental value. In terms of Regusltaion 15 of CARA, these plants will not be allowed to occur anywhere except in biological control reserves unless they were already in existence when these regulations came into effect (30 March 2001). This means that existing plants do not have to be removed by the landuser, however they must be kept under control and no new planting may be initiated and the plants may no longer be sold.

Category 3 plants include:
Jacaranda - Syringa - Australian silky oak - St Josephs lily - Sword fern - Tipu tree - New Zealand Christmas tree

 

Which Herbicides Work

There are many herbicides available. We have asked about which are most environmentally friendly, and this is the list with the most favourable first.

  • Cyanamid's Confront
  • Ranger
  • EcoGuard's Timbrel
  • EcoGuard's Garlon
  • EcoGuard's Plenum
  • Ecoguard's Access
  • Volcano's Hatchet/Cyanamid's Chopper
  • DuPont's Brush Off

This list is very important to consider as you approach a wetland. Volcano's Climax and Du Pont's Brush off are better product to consider in a wetland, water course or near running water.

How to Use

Tried and tested, here are ratios to mix herbicides.

More specific Pom-pom information is available here.

LANT SPECIES FOLIAR SPRAY CUT STUMP / FRILL
Australian Blackwood Confront @ 0.70% = 105ml/15L Confront @ 4% = 600ml/15L
or 7ml/L Or 40ml/L
Eucalyptus Grandis Confront @ 1.25% = 187.5ml/15L Confront @ 3.5% = 525ml/15L
(Blue gum) or 12,5ml/L Or 35ml/L

Eucalyptus Sideroxylon

(Iron Bark Gum)

Garlon @ 0.75% = 112.5ml/ 15L Confront @ 12.5% = 1875ml/15L
Or 7,5ml/L Or Confront 125 ml/L
Beefwood Garlon @ 0.75% = 112,5ml/15L Garlon @ 1% = 150ml/15L
Or 7,5ml/L Or 10ml/L

Honey Locust

(Driedoring)

Garlon @ 0.75% = 112,5ml/15L Access @ 3% = 450ml/15 L
Or 7,5ml/L Or 30ml/L
Bramble Confront @ 0,70% =105ml/15L  
Or 7ml/L

Bug weed

(wild tobacco)

Confront @ 0.60% = 90ml/15L Timbrel @ 3% = 450ml/15L
Or 6ml/L Or 30ml/L or Access@1%
  = 150ml/15L or 10ml/L
Lantana Access @ 0.75% = 112.5ml/15L Access @ 1% = 150ml/15L or
Or 7.5ml/L 10ml/L
Mexican poppy Mamba @ 1% = 150ml/15L  
Thorn apple/Bitter apple Or 10ml/L
Scotch Thistle Confront @ 0.75% = 112,5ml/15L  
Or 7,5ml/L
Poplar Garlon @ 1.5% = 225ml/15L Timbrel @ 6% = 900ml/15L
Or 15ml/L Or 60ml/L
Sesbania Garlon @ 0.5% = 75ml/15L Garlon @ 0.5% = 75ml/15L
Or 5ml/L Or 5ml/L
Spanish Reed Mamba @ 3% = 450ml/15L or  
30ml/L
Bankrotbos Garlon @ 0.5% = 75ml/15L  
Or 5ml/L
Syringa Garlon @ 0.75% = 112,5ml/15L or 7.5ml/L Confront @ 3% = 450ml/15L
Or 30ml/L
Wattle Confront @ 0.5% = 75ml/15L Confront @ 2% = 300ml/15L
Or 5ml/L Or 20ml/L
Wild Tomato Garlon @ 0.5% = 75ml/15L  
Or 5ml/L

Privid

(Wax Leaf)

Garlon @ 0.75% = 112,5ml/15 L Access @ 3 % = 450ml/15L
Or 7,5ml/L Or 30ml/L
Castor Oil   Confront @ 2% = 300ml/15L
Or 20ml/L
Pom Pom

Brush-Off @ 25g/100L = 3,75g/15L

or Climax @ 35g/100L or 5.25g/15L

or Access @ 0.35% = 52.5ml/15L or 3.5ml/L

 
Pampas Grass Mamba @ 3 % = 450ml/15L or 3ml/L  
Cat Bush (wild asparagus) Access @ 0.75% = 112,5ml/15L  
Or 7,5ml/L
Queen of the Night Garlon @ 1% = 150ml/15L or 10ml/L or MSMA @ 5% = 750ml/15L or 50ml/L MSMA use 1L/2L water. 1 stem injection for less than 2.5m. 2 stem injections for more than 2.5m

Monitoring

Keeping track of the extent of coverage, the effectiveness of treatment and costs is important. We have a sample monitoring form for you to download and use. Click here to download the form (Excel) (43kb)

With appreciation to GDACE Extension officers for their input, City of Tshwane and Department of Agriculture.