REPORT ON THE NATIONAL

BANKRUPT BUSH (Seriphium plumosum)

SURVEY (2010-2012)

Paul Avenant

Production Scientist

January 2015

Department of Agriculture, Forestry & Fisheries

Directorate Land Use & Soil Management

Sub-directorate: Natural Resources Inventories & Assessments

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Executive summary

Bankrupt bush (Seriphium plumosum) is an indigenous woody dwarf shrub that

encroached into mesic grassland and some savannah areas. It competes and

replaces natural rangeland at an enormous rate and scale. Based on current data,

an extrapolation was made to identify probable veld types that might be prone to

encroachment. The results indicate an area of almost 11 million hectares of

rangeland that could be lost for agricultural production. If government does not

regard this problem as serious, and actively get involved in the control thereof, it

might result in a serious threat to national food security.

The Department of Agriculture, Forestry and Fisheries (DAFF) commenced with an

investigation to the extent of this problem during the period of March 2010 to

December 2012. This was done by means of a survey form that was distributed to

farmers in the affected regions and the result of the survey is published in this

report.

The report focuses on the distribution areas of the encroachment, the habitat

preferences of the plant, the control actions farmers used and the impact thereof

on the environment. The four most common approaches are discussed and

evaluated in the report. This includes the use of herbicides, the mechanical

removal of plants and the use of fire, livestock and grazing as additional tools. In

many cases farmers use a combination of these tools to manage the encroachment

effectively. Results indicated however that the use of herbicides, although not the

most environmental friendly method, may be the only solution to make an impact

on the current extent of encroachment. Other approaches may be valuable as tools

in the management of the problem after initial control, but in most cases are too

time consuming and labour intensive to make a real impact at such a large scale.

In the report recommendations are also made in terms of the most effective control

measures and management options based on latest research conducted by

scientific institutions and herbicide companies. Research gaps and priorities are

also further highlighted in the report.

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INDEX

EXECUTIVE SUMMARY...........................................................................1

CHAPTER 1

1. INTRODUCTION…………………………………………………………………………......4

CHAPTER 2

2. LITERATURE RESEARCH…………………………………………………………………..6

CHAPTER 3

3. METHODOLOGIES

3.1 Survey forms……………………………………………………………....………….…9

3.2 Workshops…………………………………………………………………..……….……9

3.3 Field verification………………………………………………………..…………….11

3.4 Reconnaissance surveys……………………………………………..……………11

3.5 Personal communication……………………………………………………….…12

CHAPTER 4

4. RESULTS: GENERAL

4.1 PARTICIPATION IN THE NATIONAL SURVEY………………….……….. 13

4.2 EXTENT OF BANKRUPT BUSH ENCROACHMENT……………………. 15

4.3 PLANT DENSITY………………………………………………………………..…….. 16

4.4 HABITAT

4.4.1 Soils……………………………………………………………………………. 18

4.4.2 Terrain……………………………………………………………..………… 19

4.4.3 Aspect…………………………………………………………………..……. 20

4.4.4 Veld types………………………………………………………....………. 21

4.4.5 Other observations………………………………….………………… 24

4.5 MANAGEMENT HISTORY

4.5.1 Natural veld vs old lands………………………………………….. 25

4.5.2 Animal type……………………………………………………………… 25

4.5.3 Impact on veld and carrying capacity……………………….. 26

4.5.4 Frequency of veld fires…………………………………………….. 26

4.5.5 Years of infestation………………………………………………….. 27

4.6 CONTROL AND MANAGEMENT OF Seriphium plumosum…….. 28

4.6.1 Mechanical control………………………………………………….. 30

4.6.2 Chemical control……………………………………………………… 33

4.6.3 The use of animals to control Bankrupt bush…………… 35

4.6.4 The use of fire to control Bankrupt bush…………………. 38

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CHAPTER 5

5. THE WAY FORWARD

5.1 Holistic approach………………………………………………………………. 39

5.2 Monitoring and research………………………………………………….. 40

5.3 Closing comments…………………………………………………………….. 41

LITERATURE FERERENCES…………………………………………………… 42

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CHAPTER 1

INTRODUCTION

Bankrupt bush (Seriphium plumosum), previously known as Stoebe vulgaris, always has been

part of our indigenous vegetation, but slowly and somewhat unnoticed, encroached large areas

of our precious grassland to keep up to its reputation of leading to many farmer's bankruptcy.

This woody dwarf shrub can grow up to 1m high and is really built for survival. The large crown

may easily cover an area of 1m², over-shadow and pushing out all other species, especially

grasses that need to compete with the extensive root system for water and nutrients. The very

small leaves restrict transpiration to the minimum while the grey to blueish colour reflects the

harsh rays of the sun. Unpleasant smelling volatile oils keep away any browsers and fine seeds

are distributed by the wind in their millions, which can be lying dormant in the ground for more

than five years. Growing points situated just beneath the soil surface ensure the survival of the

plant against any fires or above ground damage.

Many efforts from farmers, government institutions and academic institutions were made to

fully understand and effectively control Seriphium plumosum. Physical removal, chemical

treatment with herbicides and other management tools like fire and grazing were all part of the

“trial-and-error” approach where farmers become poor and discouraged.

Currently this unpalatable, aggressive encroacher can easily be described as the most serious

threat to the mesic grasslands of South Africa. In many cases, farmers lost almost 100% of

natural veld, despite the fact that millions of rand have been spent to control or eradicate this

plant. Until recently, there was very little information available on the actual distribution and

extent of Bankrupt bush encroachment and the reasons why control actions are not successful.

Farmers were often accused of responsible for the Bankrupt bush encroachment on their farms

due to mismanagement of veld. This served as motivation for the Department of Agriculture,

Forestry & Fisheries to undertake this study.

The main objectives of this study were to create a spatial representation of the extent of

Bankrupt bush encroachment in South Africa, to collect information that can inform us about the

habitat preferences and to get a better understanding of all the factors that might have an

influence on the control of this plant. Lessons learned from the success stories as well as failures

will guide us in the way forward to effectively manage this invasion in a more sustainable

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manner, guiding the formulation / adaptation of policies and legislation and provide farmers

with a best practice manual to guide them in the control and management of Bankrupt bush.

Seriphium plumosum encroaching into grassland and destroying productivity:

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CHAPTER 2

LITERATURE RESEARCH

Seriphium plumosum, as described in Van Wyk & Malan (1997) is an indigenous, woody,

perennial shrublet, with greyish, slender and wiry branches which are intricately branched from

the ground. Branches are covered with numerous tufts of small, heath-like leaves of which the

upper surfaces are covered with white woolly hairs. The species light colour, which reflects

sunlight, woolly covering and small leaves, which reduce water loss, are adaptations to survive

long, dry summers. It is an aromatic plant, yielding volatile oil, which is also a protective measure

as the plants are seldom browsed by stock and then only when the plants are still young.

Badenhorst & Reynolds (2004). The flower heads are minute, surrounded by brownish yellow

bracts which enclosed the inconspicuous purple-tipped flowers, and are arranged in large

panicles along the branches. Characteristic globose galls covered with white woolly hairs are

often present on the plants and are frequently mistaken for the flower heads.

The threat of Seriphium plumosum as an encroacher plant has already been studied from the

early 1930’s, as mentioned by Roux (1969). Early researchers perceived that Bankrupt bush

encroachment was mainly due to overgrazing and that its growth was stimulated by fire, but

long term trials at Frankenwald reserve done by Hattingh , proved otherwise. These results, as

was written up by Krupko & Davidson (1961), showed Hattingh found little evidence that

overgrazing is a direct cause of Seriphium encroachment; in fact it actually tends to eliminate it.

Regarding burning, Hattingh finds that winter burning has little effect, but spring and summer

burning prevent establishment of seedlings. Very importantly, Hattingh’s trials also proved that

plots that neither been burnt nor grazed, have been overgrown by the weed.

The reasons for S.plumosum to be such a successful competitor and encroacher are numerous.

Snyman (2010) shows that every shrub produces thousands of seeds annually, which can easily

distributed by wind over large distances to encroach areas which were previously free of S.

plumosum. Marginal soils which were withdrawn from cash crop cultivation in the early eighties

were the first to be encroached and the low organic matter content and none or little

competition creates an ideal habitat. From here, a large seed bank was established from where

adjacent natural vegetation was invaded. Research by Wepener (2007) showed that both

degraded veld as well as veld in a good condition was encroached by S.plumosum under suitable

habitat conditions. According to trials done by Snyman (2010), veld fires stimulate the growth of

S.plumosum seeds and usually lead to an explosion of the seedling population in the following

season.

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Snyman (2010) also mentioned the general opinion of farmers that the conversion from sheep

farming to cattle farming, due to predator problems and stock theft, may have an influence in

the rapid encroachment rate of S. plumosum. This is due to the perception that sheep utilise the

young plants and often browsed the seed tops, which may have controlled its distribution in the

past. Farmers indicated that Merino and Dorper sheep definitely utilises the plants, especially at

young and flowering stages, while cattle tend to avoid browsing the plants.

The habitat preferences of Seriphium plumosum is also still a debateable issue. Although 25 of

the Seriphium species are found in the Cape Fynbos, Seriphium plumosum has a much wider

distribution throughout South Africa. (Badenhorst & Reynolds 2004). According to Roux (1969) it

is commonly accepted that Stoebe vulgaris evolved from S. cinerea (a Karoo species) by

mutation, which changed its character and enable it to invade grassveld. According to research

and observations done by Snyman (2009) in the Thaba Nchu area east of Bloemfontein, it seems

that S.plumosum initially occurred on higher altitudes that were favourable to typical fynbos

vegetation, for example the mountain plateaus of the mountains in the Eastern Free State. From

here, the seed dispersed through winds to lower altitudes where the plants are found today. The

possibility that the tiny seeds of these plants could have easily be spread over large distances by

clinging to animal wool and hides or even through transport like ox-wagen wheels, cannot be

excluded.

Knowledge about the cycles of active plant growth and of reproduction is crucial for effective

control of S. plumosum. Research trials done by Wepener (2007) in the Hartebeeshoek area in

the North-West province showed that the plants are actively growing from August to early

March. The reproductive phase, however, lasts from December to the end of May. This implies

that control should be done before the reproductive phase to prevent seeds from being

dispersed.

Snyman (2012) concludes that Bankrupt bush is very sensitive to high soil-water conditions and

will avoid wetland areas with shallower clay soils. The research of Snyman (2012) also indicates

that Bankrupt bush will avoid habitat of high soil fertility (e.g. lots of organic material or nitrogen

content) and saline or sodic conditions.

Snyman (2012) find a strong relationship between above ground phytomass production (total

amount of living organic plant matter) of grasses and plant density of S. plumosum. According to

Snyman (2012), up to a threshold of 2000 plants ha-1 a drastic reduction in production potential

of grasses occurred. At densities of 5000 plants ha-1, the root distribution of S.plumosum spread

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to such an extent that they compete more or less the same for water and plant nutrients with

the grass sward. If encroachment reaches a level of 2000 plants ha-1, regardless of further

encroachment, it has already decreased the production potential of the rangeland by about

65%.

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CHAPTER 3

METHODOLOGIES

3.1. Survey forms

Initially, it was decided to make use of survey forms to collect as much as possible information in

a relative short period of time. The format for the survey form (Appendix A), was compiled by a

task team, who decided what kind of questions should be asked to collect as much as possible

useful information, but without annoying the farmer who must fill in the questionnaire.

Questionnaires were made available in both English and Afrikaans.

Questions were arranged according to the following four main categories:

a) locality information: to locate properties by means of GPS coordinates or farm

deeds information;

b) encroachment information: to indicate the habitat, extent and density of

encroachment;

c) management history: to indicate management practises that may have an

influence; and

d) control actions: to capture methods, successes and failures of previous attempts

to control the encroachment.

Awareness of the project and distribution of the forms were done through the various provincial

departments of agriculture as well as the organized agriculture. Completed forms were sent to a

central office at the National Department of Agriculture, Forestry and Fisheries, where the data

was captured in a data table. This data table was related to spatial data sets, like the farm

boundary data set, by means of the GPS coordinates or the SG codes of the farm portions to

create a spatial data layer. This spatial layer was then used for creating distribution maps and

GIS data analyses.

3.2. Workshops

Due to the lack of response in certain provinces, it was decided to use farmer workshops as a

new approach. The workshops were arranged through the provincial department of agriculture

and resource auditors from the national department of agriculture. The workshops were mostly

attended by a few selected and leading farmers who farmed in the applicable district for many

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years as well as government officials concerned with natural resource management in the area.

Maps of the area were provided, showing farm boundaries and basic orientation features like

towns and roads. During the workshops, the attendees indicate the extent and density of

Bankrupt bush encroachment by demarcating the areas directly on the maps.

Although this method can give a very good indication of encroachment in a specific area, it still

remains a subjective method, and because the survey forms were not completed, a lot of detail

information about owners, control and management history could not be captured. To fill gaps

in data sets in a short period of time with less effort, the workshops were definitely worthwhile.

It is interesting to see, from the map in Fig 1, that there is a good correlation between the

number of survey forms received from this area and the density of the encroachment. In areas

with a very high density of Bankrupt bush, there was also a very good response to the survey. In

areas less densely encroached, farmers did not realise the seriousness of the problem and did

not bother to respond. Awareness regarding this problem plant is therefore of the utmost

importance in these areas because the quicker the farmer’s responses are to eradicate the

invasion of plants at an early stage, the better the chances are to recover his veld before

irreversible damage is done.

Fig 1. Results from the Aliwal-North workshop in the Eastern Cape.

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3.3. Field verification

Various field visits were undertaken to collect information regarding the habitat, density and

nature of the plant in its environment. To get an estimate of the number of plants per hectare in

different density classes, a typical belt transect method was used. A 100m rope was laid out to

mark the middle of the belt transect. GPS readings were recorded at both the starting and end

points. Two persons, one on each side of the rope, walked along the transect with a 1m wide

aluminum rod each and count all plants within a 1m distance from the rope. This results in a

count of plants per 200m², multiplied by 50 for the number of plants per hectare. In most cases

the Bankrupt bush encroachment are very homogeneous and results are quite accurate for a

specific area.

Fig 2. Counting plants in a belt transect.

3.4. Reconnaissance surveys

As a last resort, information was also captured by means of reconnaissance surveys done while

driving through an area. Known areas with high densities of encroachment but very little

distribution data captured as well as areas identified as probable “border cases” of extent were

identified on maps. Occurrence of plants along roads running through these pre-defined areas,

were captured by means of GPS route logs. The higher the density of the population observed,

the higher frequency of points was captured on the GPS.

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Fig 3. A Bankrupt bush GPS route log done in Limpopo

3.5. Personal communication

Some of the most valuable information was obtained through personal interaction with farmers.

Most farmers participating in the project were involved with Bankrupt bush control for many

years and provide very valuable information on the characteristics of the plant observed under

different conditions and its reaction to different type of treatments. They also gave us access to

encroached land to lay out trials and done some assessments. Especially observations in terms

of animal utilization of plants during different phenological stages and the plants reaction to veld

fires, fertilization and slashing were very helpful. All these pieces of the puzzle helped to put the

bigger picture together in understanding Seriphium plumosum.

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CHAPTER 4

4. RESULTS: GENERAL

The results of this survey will be handled according to the categories on the questionnaire used

during the survey. Overall there was a very good response to the survey, especially from the

Free State province, where organized agriculture actively participated in the process. Some

factors that influenced the response to the survey were:

i) The active involvement of organized agriculture and farmer unions;

ii) Political interference in the process;

iii) The general knowledge of the farmer pertaining to the threats of Bankrupt bush

encroachment;

iv) Lack of communication between different role players;

v) Farmers caution to provide certain information pertaining to their farms and farming

practices;

vi) Some questions on the survey forms were misinterpreted;

vii) The perception of unlimited government funding for control.

4.1 PARTICIPATION IN THE NATIONAL SURVEY

Figure 4 shows all the farms that participate in the national survey by completing the survey

forms. The number of respondents that participate in the survey is shown in Fig.5. Although

survey forms are still submitted due to the continuous nature of the project, a cut-off date was

chosen for data to be used in the final report. This report represents data captured from all

forms received during the period March 2010 – August 2012.

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Fig 4. Extent of farms participated in the national survey

Fig 5. Response to the national survey

In the survey form, farmers were asked to give an estimate of the hectares of their farms that

have been encroached with Bankrupt bush. The total area of the 1491 farming units that

participated in the survey was 423 125 ha of which a total of 150 202 ha (35.5%) was indicated

to be encroached by Bankrupt bush.

806

582

1491

0

200

400

600

800

1000

1200

1400

1600

Survey forms Owners Farming units

Response to national survey

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4.2 EXTENT OF BANKRUPT BUSH ENCROACHMENT

By merging all spatial data collected by means of the methods described in chapter 3, a map can

be compiled showing the actual distribution of Bankrupt bush encroachment in South Africa. It is

mostly the Highveld grassland areas, as described by MUCINA & RUTHERFORD 2006, which are

affected the most. The core area of distribution can be described as follow:

Limpopo province: mainly restricted to the Waterberg district

Gauteng province: mainly the eastern Highveld areas

Free State province: the eastern part of the province, about a third of the province

Eastern Cape province: mostly from Aliwal-North south to Dordrecht

North-West province: mostly areas east of Wolmaransstad

KwaZulu-Natal province: limit to the Northern sandy grassland areas

Mpumalanga province: Western Highveld and sour-grassveld areas.

Further analyses of the distribution data can be found in Chapter 4 where the habitat of

Bankrupt bush is described in more detail.

Fig 6. Distribution of Seriphium plumosum in South Africa

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4.3 PLANT DENSITY

Plant densities can be mainly obtained through two methods. The first is by an actual physical

survey counting plant numbers in a known area. The second is by visual assessment, walking

through a stand of Bankrupt bush and observe and try to correlate canopy cover to number of

plants.

The methodology for counting Bankrupt bush plants in a belt transect was described in chapter

two. In some severe cases plant densities of more than 40 000 plants per hectare were counted.

The following table show some results of actual assessments done on some Free State farms.

Table 1. Plant density for certain Free State transects

District Site Latitude Longitude Plants/ha

Zastron Commonage 1 S 30° 17’ 17,5” E 27° 04’ 35.0” 15 600

Zastron Commonage 2 S 30° 17’ 19,6” E 27° 04’ 45.0” 20 950

Ladybrand Johannasrust S 29° 24’ 44.9” E 27° 15’ 39.7” 15 000

Thaba Nchu Rietfontein S 29° 24’ 36.3” E 26° 56’ 06.8” 12 500

Harrismith Elm Villa 1 S 28° 04’ 45.0” E 28° 58’ 50.5” 7 550

Harrismith Elm Villa 2 S 28° 04’ 45.6 E 28° 58’ 54.1 4 350

Heilbron Cyferpan S 27° 23’ 16.3” E 28° 00’ 45.3” 20 000

Heilbron Holfontein S 27° 30’ 32.6” E 28° 06’ 50.4” 26 100

For the analyses of survey data, actual plant densities (plants/ha) as obtained through field

surveys, were correlated to the subjective, visual plant coverage classes used on the survey

forms. The following results were obtained for moderate size mature plants, each covering an

area of ± 0.25 m².

Table 2. Canopy cover classes relates to plant densities

Canopy cover

Plant Density

(plants/ha)

25% < 10 000

50% 10 000 - 20 000

75% 20 000 - 30 000

100% >30 000

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Visual assessments of plant densities can be very misleading because of the actual age and

crown diameter of plants. An area covered with very large, mature plants may have a high

canopy cover, but a lower than estimated density, while lots of seedlings may give the

impression of a low canopy cover, but actually have a very high plant density. For these reasons,

the information in table 2 can only be seen as broad guidelines when used in visual estimates,

and need to be verified by actual field surveys.

In contradiction to the research done by Snyman (2012), the grass sward as well as species

biodiversity, seem to survive remarkably well under plant densities of up to 20 000 plants ha-1.

Veld subjected to this intensity of encroachment, also shown the ability to recover at a very fast

rate, when the encroacher shrubs are removed, and can regain above ground phytomass

production in as little as two growing seasons under normal rainfall conditions.

To help farmers with visual assessments, plant density classes were developed for the survey

forms, accompanied by diagrams to help the respondent to visualize the distribution and density

of plants in the veld. Four classes were used e.g. 25%, 50%, 75% and 100% canopy cover. Figure

7 shows the schematic diagram and figure 8 the results from the 1475 farming units that

answered the question. In hindsight, it should have been more effective to provide more cover

classes on the survey forms. Many farmers created their own coverage classes when answering

the question, making it very difficult to analyse the data afterwards.

25% 50% 75% 100%

Fig 7. Density class diagrams

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Fig 8. Percentage of farming units in each density class

4.4 HABITAT

4.4.1. Soils

The general perception that S.plumosum only prefers well drained, sandy soils is also a much

debateable issue. The research done by Snyman (2012), was mainly restricted to the Free

State province, where, as indicated, Bankrupt bush tend to occur on well drained soils. From

the survey results, as shown in figure 9 it is clear that, although 85% of encroachment was

found on well drained soils in the sandy and loamy classes, there was also a 15% reported on

clay soils, and in some cases, even in wetland areas. In the Limpopo province, however, a

total change of character was observed, where S. plumosum tend to invade sandy wetland

areas and drainage lines. This behaviour poses a great threat to the sensitive ecosystems of

the Waterberg catchment and biosphere reserve.

32.88

44.61

20.81

1.69

Percentage farming units per plant density class

25% 50% 75% 100%

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Fig 9. Occurrence of S.plumosum per soil texture class

4.4.2. Terrain

As illustrated by a diagram on the survey forms, the land owners were asked to indicate the

terrain type where Bankrupt bush mainly occurs. Four terrain types were indicated namely:

i) Mountain crests or plateaus

ii) Mountain slopes

iii) Valley bottoms or depressions

iv) Flat or slightly undulating areas

The reason behind this question was to test the hypothesis that Bankrupt bush mainly

occurs on mountain slopes with good drainage. The results from the survey are illustrated in

figure 10. As expected, S. plumosum prefers mountain slopes and flatter landscapes as ideal

habitat, there wasn’t a significant difference compared to mountain crests, although this

was also expected compared to the hypothesis of Snyman (2009). What was, however, a big

surprise, was that 18% of plants occurred in valley bottoms or depressions. This is

contradictory to the belief that S.plumosum will avoid areas where water logging or seasonal

wetness may occur.

15%

59%

26%

Percentage occurrence of Seriphium plumosum per

soil texture class

Sand Loam Clay

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Fig 10. Percentage occurrence of S.plumosum on different terrain types

4.4.3. Aspect

In most literature on the habitat of S.plumosum, it was observed that Bankrupt bush favours

certain aspects. To test this hypothesis, a question on aspect was included into the

questionnaire. This question was unfortunately not as successful as the previous question on

terrain types. Many farmers did not understand the concept of aspect and either did not

answer the question at all or indicate all the options as possibilities. Results of the analysed

data are illustrated in figure 11.

From the results of the 1411 responses to this particular question it was evident that there

was no significant correlation between the habitat preference of Bankrupt bush and the

different aspects. The fact that the occurrence of Bankrupt bush on both of the opposite

aspects, for example North-South and East-West, were almost identical, illustrates the fact

that aspect is not such a determining factor as that was thought initially. In certain areas a

specific aspect may be favoured by Bankrupt bush, but after establishment, it will also

spread into adjacent areas of different aspect.

19%

30%

18%

33%

Percentage occurrence of Seriphium plumosum on different terrain types

Mountain crests orplateaus

Mountain slopes

Valley bottoms ordepressions

Flat or slightly undulatingareas

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Fig 11. Percentage occurrence of S.plumosum on different aspects of the landscape

4.4.4. Veld types

By using the distribution data obtained from the survey forms and additional observations, a

good correlation was found between the occurrence of Bankrupt bush and certain veld

types. The Vegetation types from Mucina & Rutherford (2006) were used for this exercise.

57 Vegetation types were identified as probable habitat where S.plumosum might occur.

From these vegetation types, 77.2% were from the Grassland biome and 22.8% from the

Savanna biome. In the Grassland biome, four Bioregions were involved namely the

Drakensberg Grassland Bioregion, the Dry Highveld Grassland Bioregion, the Mesic Highveld

Grassland Bioregion and the Sub-Escarpment Grassland Bioregion. The Savanna biome only

involved one Bioregion - the Central Bushveld Bioregion. Table 3 is showing the vegetation

types as well as the related biomes and bioregions.

N 16%

S 16%

W 11%

E 11%

NE 13%

NW 12%

SE 11%

SW 10%

0%

Percentage occurence of Seriphium plumosum on different

aspects of the landscape

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Table 3 Biomes, Bioregions and Vegetation types that includes S. plumosum

BIOME BIOREGION VEGETATION TYPE BOOKCODE

Grassland Biome Drakensberg Grassland Bioregion Stormberg Plateau Grassland Gd 3

Grassland Biome Drakensberg Grassland Bioregion Southern Drakensberg Highland Grassland Gd 4

Grassland Biome Drakensberg Grassland Bioregion Northern Drakensberg Highland Grassland Gd 5

Grassland Biome Drakensberg Grassland Bioregion Lesotho Highland Basalt Grassland Gd 8

Grassland Biome Dry Highveld Grassland Bioregion Karoo Escarpment Grassland Gh 1

Grassland Biome Dry Highveld Grassland Bioregion Aliwal North Dry Grassland Gh 2

Grassland Biome Dry Highveld Grassland Bioregion Besemkaree Koppies Shrubland Gh 4

Grassland Biome Dry Highveld Grassland Bioregion Central Free State Grassland Gh 6

Grassland Biome Dry Highveld Grassland Bioregion Winburg Grassy Shrubland Gh 7

Grassland Biome Dry Highveld Grassland Bioregion Bloemfontein Karroid Shrubland Gh 8

Grassland Biome Dry Highveld Grassland Bioregion Vaal-Vet Sandy Grassland Gh 10

Grassland Biome Dry Highveld Grassland Bioregion Vredefort Dome Granite Grassland Gh 11

Grassland Biome Dry Highveld Grassland Bioregion Vaal Reefs Dolomite Sinkhole Woodland Gh 12

Grassland Biome Dry Highveld Grassland Bioregion Klerksdorp Thornveld Gh 13

Grassland Biome Dry Highveld Grassland Bioregion Western Highveld Sandy Grassland Gh 14

Grassland Biome Dry Highveld Grassland Bioregion Carletonville Dolomite Grassland Gh 15

Grassland Biome Mesic Highveld Grassland Bioregion Zastron Moist Grassland Gm 1

Grassland Biome Mesic Highveld Grassland Bioregion Senqu Montane Shrubland Gm 2

Grassland Biome Mesic Highveld Grassland Bioregion Eastern Free State Clay Grassland Gm 3

Grassland Biome Mesic Highveld Grassland Bioregion Eastern Free State Sandy Grassland Gm 4

Grassland Biome Mesic Highveld Grassland Bioregion Basotho Montane Shrubland Gm 5

Grassland Biome Mesic Highveld Grassland Bioregion Frankfort Highveld Grassland Gm 6

Grassland Biome Mesic Highveld Grassland Bioregion Northern Free State Shrubland Gm 7

Grassland Biome Mesic Highveld Grassland Bioregion Soweto Highveld Grassland Gm 8

Grassland Biome Mesic Highveld Grassland Bioregion Tsakane Clay Grassland Gm 9

Grassland Biome Mesic Highveld Grassland Bioregion Egoli Granite Grassland Gm 10

Grassland Biome Mesic Highveld Grassland Bioregion Rand Highveld Grassland Gm 11

Grassland Biome Mesic Highveld Grassland Bioregion Eastern Highveld Grassland Gm 12

Grassland Biome Mesic Highveld Grassland Bioregion Amersfoort Highveld Clay Grassland Gm 13

Grassland Biome Mesic Highveld Grassland Bioregion Wakkerstroom Montane Grassland Gm 14

Grassland Biome Mesic Highveld Grassland Bioregion Paulpietersburg Moist Grassland Gm 15

Grassland Biome Mesic Highveld Grassland Bioregion KaNgwane Montane Grassland Gm 16

Grassland Biome Mesic Highveld Grassland Bioregion Lydenburg Montane Grassland Gm 18

Grassland Biome Mesic Highveld Grassland Bioregion Sekhukhune Montane Grassland Gm 19

Grassland Biome Mesic Highveld Grassland Bioregion Lydenburg Thornveld Gm 21

Grassland Biome Mesic Highveld Grassland Bioregion Waterberg-Magaliesberg Summit Sourveld Gm 29

Grassland Biome Sub-Escarpment Grassland Bioregion Low Escarpment Moist Grassland Gs 3

Grassland Biome Sub-Escarpment Grassland Bioregion Northern KwaZulu-Natal Moist Grassland Gs 4

Grassland Biome Sub-Escarpment Grassland Bioregion Northern KwaZulu-Natal Shrubland Gs 5

Grassland Biome Sub-Escarpment Grassland Bioregion KwaZulu-Natal Highland Thornveld Gs 6

Grassland Biome Sub-Escarpment Grassland Bioregion Income Sandy Grassland Gs 7

Grassland Biome Sub-Escarpment Grassland Bioregion Drakensberg Foothill Moist Grassland Gs 10

Grassland Biome Sub-Escarpment Grassland Bioregion Tsomo Grassland Gs 15

Grassland Biome Sub-Escarpment Grassland Bioregion Tarkastad Montane Shrubland Gs 17

Savanna Biome Central Bushveld Bioregion Zeerust Thornveld SVcb 3

Savanna Biome Central Bushveld Bioregion Dwarsberg-Swartruggens Mountain Bushveld SVcb 4

Savanna Biome Central Bushveld Bioregion Norite Koppies Bushveld SVcb 7

Savanna Biome Central Bushveld Bioregion Moot Plains Bushveld SVcb 8

Savanna Biome Central Bushveld Bioregion Gold Reef Mountain Bushveld SVcb 9

Savanna Biome Central Bushveld Bioregion Gauteng Shale Mountain Bushveld SVcb 10

Savanna Biome Central Bushveld Bioregion Andesite Mountain Bushveld SVcb 11

Savanna Biome Central Bushveld Bioregion Central Sandy Bushveld SVcb 12

Savanna Biome Central Bushveld Bioregion Loskop Mountain Bushveld SVcb 13

Savanna Biome Central Bushveld Bioregion Loskop Thornveld SVcb 14

Savanna Biome Central Bushveld Bioregion Springbokvlakte Thornveld SVcb 15

Savanna Biome Central Bushveld Bioregion Western Sandy Bushveld SVcb 16

Savanna Biome Central Bushveld Bioregion Waterberg Mountain Bushveld SVcb 17

23 | P a g e

From this layer of probable suitable habitat for S.plumosum, further refinement in ArcMap

was done by subtracting the areas of water bodies, buid-up areas, plantations, open cast

mining areas and cultivated land. The data from the 2005 LandCover Change project was

used for this analysis. After this refinement, the layer shows a probable 11 million hectares

of rangeland that are either already encroached or suitable for probable encroachment.

Figure 12 is showing the probability map for Bankrupt bus encroachment.

Fig 12. Rangeland probability map for distribution of S.plumosum

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4.4.5. Other observations

Some observations that were also mentioned in the survey were:

i ) Old lands

It seems that the infestation of old, unutilized cultivated fields is playing an important role in

the distribution patterns of Bankrupt bush. In the early 1980’s government launched a huge

project, trying to stop the cultivation of land with a marginal potential for crop production.

Instead of rehabilitate these areas back to veld or planted pastures, many farmers just left

the areas to let nature go its course. This provided an ideal opportunity for the opportunistic

Bankrupt bush to colonise these areas without any competition of neighbouring plants, as in

the case with natural veld. From here the plants establish strong colonies and seed banks

that invade adjacent natural veld. In the survey, 61% of farmers indicated that the Bankrupt

bush started on old cultivated fields.

ii) Road reserves

Road reserves provide a safe haven for Bankrupt bush seedlings to establish. Especially road

reserves along smaller arterial roads where the road reserves are not frequently being

slashed or burned. Many farmers complained about unattended road reserves that re-

invade previously cleared areas. On the contrary, road reserves that are frequently burned

or slashed seem to have less encroachment than on the other side of the fence.

iii) Natural veld with a good veld condition

Seriphium plumosum will establish itself also in natural veld with a good veld condition, but

in many cases infestation is well correlated to veld that is under-utilized. Many farmers

believed that, by just leaving veld to rest it will suppress the Bankrupt bush by competition.

Unfortunately the opposite is true. Veld that is under-utilised and has a good canopy cover

provides a very safe haven for the vulnerable seedlings of the Bankrupt bush to establish.

Veld that is moderately grazed tends to have less Bankrupt bush plants and also a poor

seedling survival rate.

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4.5. MANAGEMENT HISTORY

4.5.1. Natural veld vs old lands

One of the most frequently asked questions by farmers were if it’s the farmer’s fault that

bankrupt bush invades his natural veld. This question is not that easy to answer. In some

cases, by overgrazing veld, areas with little competition will make it easy for Bankrupt bush

to establish, because it then acts as a pioneer plant. Veld that are under-utilise will also

create a safe haven to seedlings. Taking this into account, one may argue that good veld

management practices may decrease the risk of Bankrupt bush encroachment. However,

one of the most mentioned problems in the survey was the fact that a farmer has no

defence against dense populations of Bankrupt bush in the adjacent areas to his farm. In this

case, no matter how perfect his veld management is, the Bankrupt bush will eventually find

its way into his veld by means of its millions of air born seeds. In mostly all cases, the major

pattern of distribution of Bankrupt bush is in the same direction as the prevailing winds in an

area. As already mentioned in 4.4.5.i, old cultivated fields that were left unattended also

created suitable habitats and farmers need to establish planted pastures on these areas.

4.5.2. Animal type

The purpose of this question was just to establish if there was any correlation between a

specific type of livestock and the problem of Bankrupt bush encroachment. The impact of

different types of livestock will be handled in more detail in Chapter 5 dealing with control

measures through the use of animals. The graph in figure 13 shows the results from the

survey on the question of the history of animal presence in the infested camps.

Fig 13. Animal types kept on S. plumosum encroached veld

63.44%

26.67%

9.01% 0.54% 0.34%

Animal type on encroached veld

Cattle

Sheep

Game

Horses & Donkeys

Goats

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4.5.3. Impact on veld and carrying capacity

The purpose of question C, under management history, was to get an idea of the impact of

Bankrupt bush encroachment on natural veld, in particular, the grass sward. The farmers

were asked to indicate the long term grazing potential of the veld (as in a good veld

condition), and then the carrying capacity of the veld after the Bankrupt bush encroachment

became a problem. The preferred units was ha/Large Stock Unit (LSU). In the majority of

cases, farmers lost between 30 – 60 % of their grazing capacity. As the Seriphium plumosum

plants mature, they suppress natural vegetation until the area became a “green desert” with

nothing else than Bankrupt bush alone. In this way it does not only decrease the carrying

capacity of veld, but also destroys the plant biodiversity of the area. Large plants may easily

cover up to 1m² with their canopy, blocking out sunlight necessary for other plant species to

survive while also depriving other plants from valuable moisture and nutrients with its

extensive root system.

This loss of veld and carrying capacity has detrimental effects on the economics of a farming

enterprise. Let’s look at an example of a farmer who has a farm with 1000 ha of natural

rangeland with a long term grazing potential of 6 ha/LSU, it means that the farmer can keep

about 166 LSU on his farm. If a Bankrupt bush encroachment of 50% decreases the carrying

capacity to 12 ha/LSU, the farmer can now only keep 83 LSU on the land. This results in a

50% loss in income. According to the June 2014 price list for live animals, from the Feedlot

Association of South Africa, a price of R20.36/kg is paid. The income for a large stock unit

(LSU) of 450kg is therefore R9 162.00 per LSU. This adds up to a possible annual loss of

R760 446.00 .

Although this example is only based on a farm of 1000 ha, one can imagine what the figure

will be if all of the 11 million hectares of predicted habitat only lost half of its potential. In

the mean while there are already a lot of farms that lost 100% of rangeland production.

Taking all of this into account, no other natural disaster like drought, fire or pest and disease

have such an impact on the biodiversity of the grassland and savanna biomes and the stock

farming industry.

4.5.4. Frequency of veld fires

This question (History D) was aimed at the history of burning frequency on a farm and its

probable impact on S. plumosum. A very wide range of answers were received, varied from

almost never to every year. Overall it doesn’t seem if there was any correlation between the

27 | P a g e

frequency of veld fires and the occurrence of S. plumosum. Many farmers indicated that fire

tend to increase the numbers of Bankrupt bush plants and stimulates the germination of

seedlings. The actual impact of fire on Bankrupt bush will be discussed in Chapter 5 under

the heading of fire as management tool.

4.5.5. Years of infestation

This question (History E) gives a very good indication of the timeframe of this problem. A lot

of farmers indicated that S. plumosum has been present on their farms for many years, but

only became a serious problem during the last 10 years. Farmers initially didn’t bother to

eradicate the plant because it didn’t occur in such high numbers (as it is currently the case)

and did not have such a detrimental effect on rangeland. By the time that the farmer starts

noticing a problem, it was already too late to implement effective control measures.

Fig 14. Number of years farms have been encroached by S.plumosum

20%

35% 15%

19%

1% 5%

5%

Number of years farms have been encroached by S.plumosum

1 - 5 yrs

6 - 10 yrs

11 - 15 yrs

16 - 20 yrs

21 - 25 yrs

26 - 30 yrs

> 30 yrs

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4.6. CONTROL AND MANAGEMENT OF Seriphium plumosum

In the national survey, in the section pertaining to Control Actions, 80% of farmers indicated

that they already attempted to eradicate Bankrupt bush on their property, without any

financial assistance from government. 20% of farmers however indicated that they have

never attempted to control Bankrupt bush. Many farmers spend lots of money on fruitless

efforts to control Bankrupt bush because they did not follow a few simple guidelines to be

successful in their effort.

The control of S. plumosum can be done in many ways; some are more successful than

others. In most cases it is the best to use a combination of control methods, firstly to

reduce the number of plants drastically and thereafter manage the situation to keep

numbers low or eventually eradicate the infestation permanently. This section will illustrate

some of the success stories and some of the less successful stories as captured in the survey

section on control actions.

In general a few important points on control of any invasive plant species:

Timely follow up is critical. A common mistake is to clear too large area initially and budget

and time run out to do timely follow up. The golden rule is to plan your control programme

over a three year or longer period and budget accordingly. First do required follow up before

clearing new areas. Initial clearing without timely follow up invariably results in denser

infestations if left unattended.

i) Always try to keep un-infested areas clean.

Rather concentrate initial control efforts on small and new colonies at the perimeter of an

infestation than to spend too much effort on the centre, dense infestation, where all

natural veld are already lost.

Fig 15. Strategy to control colonies of bush encroachment.

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ii) Supervision is extremely important.

Almost all the cases of failure are in some way connected to poor supervision of control

teams. Supervisors need to be on-site all day and need to check if all areas or plants are

treated, if herbicides are prepared correct and if correct dosages are applied. In manual

control, supervisors must make sure that equipment is in good working order and that it is

used correctly.

iii) Training.

Training will always be an important factor in any control action. Firstly make sure that the

trainers are certified and registered trainers to provide the specific training. Also ensure

that everyone involved in the control, are properly trained and are capable to do what is

expected from them.

iv) Safety

Safety of workers must always be a number one priority. Safety training must highlight all

probable risks to the workers and how they can avoid it. All safety equipment must be

issued and workers must sign that they received it and know how to use it.

The next section in the survey focused on the control methods used in the control of

Bankrupt bush. The four options were:

i) Mechanical

ii) Chemical

iii) Grazing

iv) Fire

Many farmers also indicated that they have used different combinations of the above

mentioned methods. The results from the survey are shown in the graph below:

Fig 16. Control methods used by farmers

35%

24%

22%

19%

Control methods used by farmers

Mechanical

Chemical

Grazing

Fire

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4.6.1. Mechanical control

Mechanical removal of Bankrupt bush can either be done by hand or through machinery like

tractors to disk, plough or slash. Removal by hand is usually done with a pick-axe (“bospik”)

or hoe. In many cases, an ordinary hoe is too light to really cut deep enough to remove the

burl of the stem, which is situated just beneath the soil surface. The wide hoe blade just cut

off above-ground stems, leaving the growth points to start regrowth within a week.

Fig 17. Above-ground stems cut off with a hoe.

Fig 18. Growth points started to sprout from the underground burl.

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Fig 19. The hoe (left) is not as successful as the pick-axe “bospik” (right) to remove plant

roots deep enough.

From all the mentioned methods used by farmers for mechanical removal of plants, the

chopping out of plants by means of a hoe or pick-axe was by far the most popular method

used. This method was mainly limited to plants that invade natural veld with low plant

densities of up to 5000 plants/ha. For higher plant densities it is more efficient to use

herbicides. Disking and ploughing were mainly used in previously cultivated fields and many

farmers also indicated that they established these fields with planted pastures afterwards. It

seems however that some planted pastures with less dense growth forms, like Digitaria

eriantha, may be easily invaded by Bankrupt bush, especially in the first year of

establishment. Slashing of plants was also used by some farmers and although this method

is not removing the plant, many case studies indicated that plant numbers will decrease

through continuous slashing.

Fig 20. Mechanical methods used by farmers to control Bankrupt bush.

83%

7%

10%

Mechanical methods used by farmers

Hoe or pick

Slash

Disc & Plough

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When removing plants mechanically, some farmers tend to pile-up the chopped out plants.

This is for obvious reasons, because it made it easy to see where control has been done and

what the progress is but unfortunately there is also a few disadvantages. Seeds are

dispersed to other areas as plants are dragged to the pile. In many cases, these piles are

then burned. The heat of such an intense fire is sterilizing the soil beneath and these open

patches of sterilized soil will take a very long time to restore, giving ample opportunities for

other weeds and invasive plants to establish there. Even if piles are not burned, but only left

as such, they become a very serious fire hazard. In the event of an unplanned veld fire, these

piles will create their own drafts, causing the uprooted plants to be scattered all over the

place as flying torches that will ignite anything they touch.

Fig 21. Piling-up of uprooted Bankrupt bush.

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4.6.2. Chemical control

Chemical control still remains the most cost effective way to control dense infestations of

Bankrupt bush. The use of herbicides in the natural environment will always be regarded as

a sensitive issue, and in the case of Bankrupt bush control it is no exception. Unfortunately

environmentalists always defend their position using the cases of wrong application or

dosages that caused major damage to the environment. On the other side are the herbicide

companies claiming years of research and experience developing safe and effective

herbicides. The other major factor that influences herbicide control is cost. Most farmers

used cheaper herbicides, not always developed for the results that the farmer has in mind.

When analysing the options of herbicide control available for S. plumosum there are mainly

two active formulas used namely Tebuthiuron and Metsulfuron;

Tebuthiuron is a non-selective broad spectrum herbicide of the urea class. It is used in a

number of herbicides manufactured by Dow AgroSciences, and is sold under several trade

names, depending on the formulation. The most popular trade names used in South-Africa

are Molopo and Limpopo and are available as granules or suspensions. Tebuthiuron is a

systemic herbicide absorbed by the roots and inhibiting photosynthesis. Application is by

means of aerial or ground broadcast or as spot application by means of a knapsack sprayer

or granules per plant. After application, rain is needed to wash the herbicide into the soil,

reaching the plant roots from where it is absorbed. It takes up to 24 months for large plants

like trees to die and about 12 months for a shrub like Bankrupt bush. Over dosage is a big

risk, especially with spot application of granules. Great care need to be taken to prevent

over dosage and farmers must make sure that the over-all application of granules per area is

not too high. Over dosage can lead to sterilising the soil and dying of all plant life, leaving

areas of bare soil with a high risk of erosion (DU TOIT 2012). Tebuthiuron is a very effective

herbicide recommended to quickly get rid of large and dense infestations of Bankrupt bush.

One of the biggest benefits is the 3 year active period of the herbicide that will also kill off

any seedlings germinating during this period. One of the biggest challenges with spot

application is not to miss any plants. A colour stain is added to the herbicide making it easy

for the controller to see which plants have been treated. Spot application is much easier

after most of the old and moribund material was removed and enough new growth achieved

to absorb a sufficient amount of herbicide that can be trans-located to the roots. Regrowth

after a burn provides an excellent opportunity. Spot application is only recommended for

plant densities of less than 4000 plants/ha. Denser populations can be treated by means of

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broadcasting of granules or spraying with tractor sprayers or in more inaccessible areas by

means of aerial application with a light aeroplane.

Fig. 22 Tebuthiuron as a suspension (left) or granules (right)

Metsulfuron-methyl is a residual sulfonylurea herbicide that kills broadleaf weeds and some

annual grasses. It is a foliar applied systemic compound which inhibits cell division in shoots

and roots. It has no residual activity in soils, allowing it to be used frequently. It has very low

toxicity to mammals, birds, fish, and insects. Metsulfuron must be sprayed onto the foliage

of actively growing plants with a single application during the active growing period

(October to April) and preferably during the late summer (January to end April) but before

the onset of winter. Removing the dead foliage of S. plumosum by means of slashing or

burning before application will improve uptake of the herbicide and result in better control.

Slashing can however result in the release of ample seed, which will have to be controlled

the following season. Trade names of Metsulfuron-methyl in South-Africa such as Brush-off

and Climax are very popular with farmers because they are usually not that expensive, but

farmers do not always take into account the fact that they need to apply the herbicide for at

least 3 consecutive years to achieve the same results as for example with Tebuthiuron. This

adds up to quite an expensive exercise. One of the big challenges with the use of

Metsulfuron is that it also required large quantities of water to prepare the suspension,

which in some remote areas are not always possible. Metsulfuron has however a very

important role to play as a follow-up herbicide after the use of Tebuthiuron. Because of the

harsh impact of Tebuthiuron on the environment and its residual build-up in soil, it is not

recommended to be use for two consecutive cycles of treatment in an area. Metsulfuron

provide a good and safe substitute to control the remaining few plants that managed to skip

the Tebuthiuron treatment.

35 | P a g e

Fig 23 . Some popular herbicide trade names

Other herbicides used by farmers were Access, Browser and Garlon from the Triclopyr and

Picloram active ingredients. Roundup from the Glyphosate active ingredients and

Bushwacker and Savanna from the Bromacil active ingredients. Although salt will kill

Bankrupt bush, the negative impact on the environment and the danger of salination of soils

creates a much bigger environmental threat than the Bankrupt-bush itself. It is therefore not

recommended at all for farmers to use salt in the control of Bankrupt-bush.

The following survey results shows which herbicide products were the most popular with

farmers:

Table 4. Herbicides used by farmers to control S.plumosum

ACTIVE INGREDIENT TRADE NAME PERCENTAGE

Metsulfuron-methyl Romex 8.25%

Climax 17.75%

Brush-off 31.81%

GROUP TOTAL 57.81%

Tebuthiuron Molopo 28.30%

Limpopo 2.81%

Grazer 0.18%

GROUP TOTAL 31.29%

2,4 D Ester 2,4 D Ester 4.57%

Tebuthiuron x Bromacil Savanna 1.05%

Bromacil Bushwacker 0.18%

Glyphosate Round-up 2.11%

Sodium chloride Salt 2.99%

HERBICIDES USED BY FARMERS

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4.6.3 The use of animals to control Bankrupt bush

Animals will usually not browse on Bankrupt bush, due to the presence of bitter tasting

essential oils. However, a lot of farmers indicated that cattle will browse the plants

occasionally and that sheep quite often will browse on the flowering tops of the plants. For

this reason, many farmers reason that the Bankrupt-bush encroachment increased when

farms shifted their farming commodities from large stock to small stock.

Although browsing animals will suppress the growth of Bankrupt bush, it will rarely manage

to kill the plants, but their hoof action turned out to destroy quite a significant number of

seedlings, and thus contribute to control. On the contrary, to withdraw animals from

infested veld and think that the grass sward will eventually suppress and kill Bankrupt bush,

is not only a misperception but can even worsen the situation. The dense grass sward will

create a safe haven for the vulnerable seedlings to survive and become strong plants. The

best results will be achieved by following normal grazing regimes while controlling Bankrupt

bush. Some game species like Rhinoceros and Eland will often browse Bankrupt bush as part

of their normal diet.

It is also proven that Bankrupt bush is sensitive to high organic content in soils. The animal

dung and urine provides an unfavourable environment for Bankrupt bush to flourish in, and

especially for seedlings to survive. Some farmers who have access to huge amounts of

animal dung, for example feedlots, started to cover the Bankrupt bush infested veld with

about 4 t/ha of animal dung. This will only help to keep the plants within controllable limits,

but will probably never eradicate all plants. The question however arises what the impact of

this practice will be on the veld itself and underground water reserves after leeching of

harmful nitrates into the soil.

Fig 24. Animal dung

and high intensity

grazing (left camp)

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The photograph above shows a very clear fence line effect after the camp on the left was

treated with 4t/h of animal dung and also heavily trampled and grazed through high

intensity grazing. Although it looks like the Bankrupt bush disappear, many plants are still

present, but only overshadowed by a very healthy and vigorous grass sward.

It seems that continuous defoliation of Bankrupt bush may contribute to suppress the plants

and that numbers will eventually decrease. If animals are not an option, even mechanical

defoliation may be used. The photograph below shows an area in a game reserve, where the

manager slashes the Bankrupt bush twice during the growing season. This also will not

remove the plants in total, but definitely decrease its numbers.

Fig. 25 Natural veld slashed to suppress Bankrupt bush

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4.6.4 The use of fire to control Bankrupt bush

Fig 26. Burning Bankrupt bush creates a very high intensity fire.

Fig 27. Bankrupt bush sprouts just one week after burning.

The two pictures above shows the amazing ability of Bankrupt bush to survive a fire. Due to

the growing points that are safely hidden below the soil surface, the plant manages to

escape death by fire without any trouble. It is thus important to note that a farmer will

never be able to totally eradicate Bankrupt bush only by the use of fire, but it can still be a

very handy tool to assist in control. Especially in very dense stands of old and moribund

39 | P a g e

plants, fire can be very helpful to remove the above ground plant material in order to ease

access into the area for control teams, either using herbicides or chopping out plants. New

growth can easily be seen and individual plants can easily be identified to be hoed out or

treated with herbicides. Herbicides are also absorbed much more efficient by the new

growth and less liquid application is wasted on moribund material. It is however extremely

important to burn only in safe conditions and when ample fire fighters and equipment are

on standby. Because of the essential oils in Bankrupt bush, it creates an extremely hot and

intense fire that is almost impossible to stop once it is started. Very broad firebreaks and an

adequate supply of water will be needed to burn a block of Bankrupt bush safely.

Just remember that fire will always be a very detrimental tool. It removes all organic debris

and totally denudes the soil compared to slashing that leaves an organic blanket on the

surface that retains moisture, feeds the soil and suppresses establishment of bankrupt bush

seedlings.

Some research also indicated that burning will stimulate seed germination, and many times

after a burn, huge population explosions of seedlings are noticed. This creates a good

opportunity to treat the area with a herbicide that will have a long after effect, or using

animals to trample the seedlings and browse on new growth.

Research also indicates that a burn during early summer (November / December) will cause

the most damage to mature plants. This is also unfortunately the time of the year that a

burn will do the most harm to the grass sward. In dense stands of Bankrupt bush, where

very little of the grass sward is left, it is an option, but otherwise other options may be

considered. Burning in spring will cause the greatest damage to seedlings.

5. THE WAY FORWARD

5.1. Holistic approach

If one looks at the current situation of Bankrupt bush encroachment, the most honest

conclusion will be that we will never totally eradicate this problem. Seriphium plumosum is

here to stay. The big question is how we are going to manage this problem, mitigate its

impact, rehabilitate areas that can still be rehabilitated or are worthwhile to restore, and

prevent future encroachment.

40 | P a g e

It is however very important to realise that the only effective way of management will be at

district or catchment level and not at farm level. Infestations need to be eradicated as total

populations and not just as small colonies between farm boundaries. This will be a huge

challenge and will probably need a significant amount of dedicated funding from

government’s treasury.

This brings us to the issue of prevention and mitigation. If each farmer is willing to take

responsibility for his own farm, even if it’s not through control but only prevention, the war

is already half won. Contain heavily infested areas and aggressively eradicate every plant

that dares to grow within the buffer zone of this area. Also regularly inspect healthy,

uninfected veld for signs of seedlings and immediately act. Then, as money becomes

available or aid schemes from government, treat the heavy infested populations and make

sure that there will be a follow-up plan for at least 5 years afterwards. Prevent excessive

seed dispersal by not moving uprooted plants from one area to another. Browsing, slashing

or burning just before plants started to seed may contribute to success.

5.2. Monitoring and research

The effectiveness of management of almost anything relies on the research behind it. Just

think how much research already gone into herbicide development for example. For

Bankrupt bush to be effectively managed, a lot of research is still needed. The first question

on where it occurs and to what extent, is already answered at a national level by this survey.

The monitoring will need to continue to paint a clear picture on the success or failure of

efforts to contain this problem. One of the most promising advancements in the field of

monitoring is the use of satellite imagery and spectral signatures to identify certain species.

If this can be done for Bankrupt bush, it will enable us to monitor on a much finer scale,

identify priority areas of intervention and rapidly respond when new populations appears in

an area. Research gaps include the following:

The habitat description of Seriphium plumosum at a national scale.

The viability of seed under natural conditions

The impact of both large and small stock digestive system on the viability of the

seed of Seriphium plumosum.

Probable use of the essential oils in the plants.

Investigate natural enemies to control plant numbers (e.g. gals killing some plants)

41 | P a g e

Quantitative measurements on the impact of animals (browsing, trampling, dung)

on the survival of the seedlings and mature plants.

Herbicides with less impact on the environment but more effective on woody

dwarf shrubs.

5.4 Closing comments

As shown in this survey, Bankrupt bush has been with us for many decades. At first you only see

one or two near a fence line, and after another year you find a small population within a road

reserve, and then, one morning after a few decades, you find nothing else but Bankrupt bush on

your farm!

In this current period that we are moving towards, climate change will increasingly play a role in

the appearance of indigenous woody species that started to encroach our precious grazing land,

slowly at first, but then, one morning ………

It is extremely important that when farmers look at their veld, that they will look at it from an

holistic way and not just concentrate on one problem, but rather see how to influence the

overall health of the agro-ecosystems, that provides production, ecological as well as social

cultural services needed to maintain and enhance their livelihoods, if used in a sustainable and

in an environmental friendly way.

Any farmer who is serious about farming will realise that he or she farms with the natural

agricultural resource, in this case rangeland and not the commodity (livestock). Farmers

neglecting or ignoring their duty as caretakers of the natural resources and who do not prioritize

the protection, conservation and sustainable use thereof, may just as well declare a state of

bankruptcy – which will happen if you ignore the threat of Bankrupt bush!

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6. References

BADENHORST & REYNOLDS 2004. PlantZAfrica.com website. South African National Biodiversity

Institute. Cape Town.

COLEMAN, A. 2010. Great strides in the fight against Slangbos encroachment. Game & Environment.

Farmers Weekly. 5 February 2010 edition. p.60-61.

DU TOIT, J.C.O. & SEKWADI K.P. 2012. Tebuthiuron residues remain active in soil for at least eight

years in a semi-arid grassland, South Africa. African Journal & Forage Science. 29(2): 85-90.

FEEDLOT ASSOCIATION OF SOUTH-AFRICA website: http://www.safeedlot.co.za – For livestock

prices mentioned in Chapter 4.5.3

JORDAAN F.P. & JORDAAN D.G. 2012. Seriphium plumosum, Bankrotbos – Die weiveld dief in die

Noordwes Provinsie. Department Agriculture and Rural Development, North West Provincial

Government.

KRUPKO, IRENA & DAVIDSON, R.L. 1961. An experimental study of Stoebe vulgaris in relation to

grazing and burning. Empire Journal of Experimental Agriculture. 29:175-180.

MUCINA, L. & RUTHERFORD, M.C. (eds) 2006. The vegetation of South Africa, Lesotho and

Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria.

ROUX, E. 1969. Bankrotbos. In: Roux, W.M. (Ed.), Grass, A story of Frankenwald. Oxford University

Press, Cape Town. p153-159.

SNYMAN, H.A. 2009. A philosophical approach to the distribution and spread of Seriphium

plumosum. Grassroots; publication of the Grassland Society of Southern Africa. Vol. 9 (2).

p. 29-37.

SNYMAN, H.A. 2010. Knowledge of seed ecology essential for Seriphium plumosum control.

Grassroots; publication of the Grassland Society of Southern Africa. Vol. 10 (1). p. 9-14.

SNYMAN, H.A. 2012. Habitat preferences of the encroacher shrub, Seriphium plumosum. South

African Journal of Botany. 81: 34-39.

VAN WYK, A.E & MALAN, S.J. 1997. Field Guide to the Wild Flowers of the Highveld. Struik, Cape

Town. p44 & 272.

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WEPENER, J.P. 2007. The control of Stoebe vulgaris encroachment in the Hartebeesfontein area of

the North West Province. North-West University, South Africa.

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APPENDIX A

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