Lopholaena coriifolia Small-Leaved Fluff-bush Pluisbos

pluis bos

[Download as Factsheet in English or Afrikaans]

Description: A perennial, erect (>1m high) woody shrub with briefly attractive fluffy white blooms in spring (October)); grey-green leaves succulent, leathery. Stem becomes dark and woody with growth, with dark brown flaking bark.

 

Origin: Indigenous to most of Mpumalanga, Limpopo provinces and Swaziland.

Occurrence: On roadsides, in open montane grassland and on rocky hillsides in wooded grassland. Often occurs in proximity to bankrotbos (Seriphium plumosum, formerly Stoebe vulgaris) in former, over-grazed lands in the Waterberg, especially in moister areas peripheral to wetlands.

Why it is a problem: Lopholaena is unpalatable to animals; once established in overgrazed veld, it spreads rapidly together with bankrotbos and can become a serious invader that causes degradation and reduced biodiversity.

Elimination / Control Methods: Problematic because the destruction of above-surface parts by fire or herbicides can stimulate rhizomes to shoot and produce more flowers; but repeated application can be successful.

Physical removal, including the removal of budding flower heads, can control and eventually eliminate the plant; physical removal is easier than for bankrotbos.

Herbicides should be applied as early as possible in the growing season, preferably before flowering. All require the addition of a surfactant (which includes a wetting agent), the name of the preferred one usually being given with the instructions for use;

All herbicides should be used when freshly mixed (do not leave the solution overnight).

NB: Follow carefully the instructions provided on herbicide label. Many herbicides can be toxic to other plants and or game and livestock if used inappropriately. (Mis-use of herbicides is also a criminal offence in terms of Act No. 36 of 1947).

Only two herbicides are registered for control of Lopholaena, both based on the active ingredient picloram, which is very successful. Registered herbicides are:

Access 240 (L4920)(picloram 240 g/L, a potassium salt):a liquid. Use the surfactant Actipron, or BP Crop Oil. Apply to foliage from November to January.

Browser (L7357) (picloram 240 g/L, a potassium salt):a liquid.

Both these products are intended for foliar application, and can be applied using a knapsack sprayer with the recommended surfactant and / or foaming agent.

  

infestation pluis bosInfestation of Lopholaena coriifolia on high ground, Tarentaalstraat

 

References:

 

ARC-LNR SAPIA News 28 (April 2013). ARC – Plant Protection Research Institute, Pretoria. www.arc.agric.za

Bromilow, Clive (2010): Problem Plants and Alien Weeds of South Africa. Briza. Pretoria.

Schmidt, Ernest; Mervyn Lotter & Warren McCleland (2007): Trees and Shrubs of Mpumalanga and Kruger National Park (2nd Edition). Jacana, Johannesburg.

Van Zyl, Kathy, (compiler) (2005): Control of Unwanted Plants. Xact Information, Pretoria.

Van Zyl, Kathy, (compiler) (2012): Problem Plant Control Compendium. AVCASA, Midrand

(This email address is being protected from spambots. You need JavaScript enabled to view it.)

 

Special thanks to Dr Gerhard Verdoorn of Griffon Poison Information Centre, to Mr Ferdie Jordaan

of Arysta Lifescience and to Ms Lesley Henderson of ARC for their invaluable advice and guidance. Their enthusiastic support for this voluntary project is greatly appreciated.

Cereus jamacara / Queen of the Night / Nagblom

Dense clump of nagblom                                            Spines occur in clusters of 5-10

[Download the Fact Sheet in English or Afrikaans]

          

Description: A spiny, tree up to 7 m high with multiple winged, thick, succulent vertical branches arising from a short woody trunk.

NB: Superficially resembles the naboom (Euphorbia ingens), but can easily be distinguished from all indigenous Euphorbia by:

1) its clusters of 5-10 spines (the others are spineless or have a single or a pair of

   spines); and

2) the fact that it does not exude a milky latex when cut.

Its name is due to the attractive white flowers produced in spring/early summer and which open mainly at night and close again at dawn. Like many cacti, it produces an edible, yellow-pinkish red fruit, the seeds of which are spread by monkeys and birds.

          

Origin: Introduced from South America (Brazil) as an ornamental plant and barrier hedge.

Occurrence: It invades rocky ridges and savanna, growing under and among trees. It is particularly prevalent in Mpumalanga and in southern Limpopo and is readily seen along the road from Vaalwater to Melkrivier.

 

Why it is a problem: It replaces indigenous vegetation and prevents animals from accessing food and shade. Chopped or broken branches readily take root and form new plants.

It is a declared Category 1 invader weed and its removal is mandatory. It is particularly important to eradicate this invader while serious infestations are still uncommon.

Elimination / Control Methods: This plant is relatively easy to eliminate, either physically or using herbicides. As with other cacti, it is also very successfully controlled using biological agents, which have the advantage of not creating any herbicidal risks – see below – but which are much slower in achieving the same results.

The plant can be cut down and its extensive root system dug up; however, great care should be taken during removal of the parts of the plant to ensure that none are left behind or along the way. All parts of the plant should be burnt (although it is also possible to bury them deeply).

Herbicides should be applied early in the growing season.

Note that:

-        All herbicides should be used when freshly mixed (do not leave the solution overnight).

-        NB: Follow carefully the instructions provided on herbicide label. Many herbicides can be toxic to other plants and or game and livestock if used inappropriately. (Mis-use of herbicides is also a criminal offence in terms of Act No. 36 of 1947).

The principal herbicide registered for use against the plant, with great success, is MSMA 720 SL (L7279). Dilute 1 litre of MSMA in 2 litres of water and inject the solution into pre-made holes in the stem of the plant at ~2.5m intervals, with only 2 ml per hole. Repeated treatment of up to 8 injections may be necessary.

NB: SANBI has advised that MSMA has recently been withdrawn from use by state departments because in isolated cases, it has been found to be highly toxic to grazing stock and wildlife, as it readily contaminates the grass surrounding the target plants. However, MSMA can be used safely if it is injected into the target plant, not sprayed onto it. It is strongly advised that the area to be treated is enclosed by a simple temporary fence to keep livestock and game out; and that the treated plants, once they have died off, are collected, burned in a pit and covered over with soil, before allowing animals into the area again.

The active herbicide ingredient glyphosate has also been registered for use against this and some other cacti, although it does not deliver results as good as MSMA. Numerous herbicides containing this chemical that have been registered, for example Duiker 180, Roundup Max, Nexus, Cobra, Springbok.

Biologically, some success has been reported from the use of the stem borer Alcidion cereicola, which was released in 1990.

 

References:

ARC-LNR Weeds & Invasive Plants website: www.agis.agric.za/wip

ARC-LNR SAPIA News 25 (July 2012): ARC – Plant Protection Research Institute, Pretoria. www.arc.agric.za

Bromilow, Clive (2010): Problem Plants and Alien Weeds of South Africa. Briza. Pretoria

Henderson, Lesley (2001): Alien Weeds & Invasive Plants. Agricultural Research Council (ARC), Pretoria.

Van Zyl, Kathy, compiler (2005): Control of Unwanted Plants. Xact Information, Pretoria.

Van Zyl, Kathy, compiler (2012): Problem Plant Control Compendium. AVCASA, Midrand

(This email address is being protected from spambots. You need JavaScript enabled to view it.)

Special thanks to Dr Gerhard Verdoorn of Griffon Poison Information Centre, to Mr Ferdie Jordaan of Arysta Lifescience and to Ms Lesley Henderson of ARC for their invaluable advice and guidance. Their enthusiastic support for this voluntary project is greatly appreciated.

Alien Acacia species, wattles, mimosas, wattels

Acacia mearnsii

[Download as Factsheet in English or Afrikaans]

Acacia mearnsii...............black wattle / swartwattel

Acacia dealbata................ silver wattle / silwerwattel

Acacia decurrens.............. green wattle / groenwattel

Description: Like all but one of the 960-odd mis-named acacias or wattles of Australasia, these three species are without thorns (‘mis-named’ because the very word acacia is derived from the Greek akis, for a sharp point – i.e. thorns - as occur on all African acacia species, north Africa being the type location for the genus). A. mearnsii, the most important of the three, is an evergreen tree up to 15m high, with a dark trunk, branchlets shallowly ridged and all parts finely hairy. Raised glands occur at and between the junctions of pinnae pairs. Its leaves are a dark olive green and bipinnate, with short, crowded leaflets. Its flowers are pale yellow or cream balls, as large fragrant flowerheads, in July-September. Its fruits are dark brown pods, usually markedly constricted. A. decurrens is almost hairless and its leaves are a bright green in comparison with A. mearnsii, with bright yellow flower balls and hairy, brown, slightly constricted pods. A. deelbata, easily confused with A. mearnsii, has branchlets that are tinged grey or purple, but with glands only at pinnae pair junctions, with silvery-grey leaves and greyish to purple-brown pods, only slightly constricted.

 

NB: Take care not to confuse these alien wattle species with the indigenous tree Peltophorum africanum, the African-wattle or huilboom, which has a superficially similar appearance, especially when in bloom. The trunk of P. africanum is browner than that of the alien wattles; and, most diagnostically, its yellow flowers are produced in large, petalled, leguminous sprays, not in balls.

          

Origin: Of a total of 18 alien species ofacacia or wattle introduced into South Africa from Australasia / SE Asia and cultivated for timber, shelter and firewood, only three are found in significant numbers in the Waterberg and all three are declared invaders or weeds. A. mearnsii was introduced into KZN in the 19th century for the production of tannic acid used in the leather industry; and for timber. It is still planted commercially, unlike the other two species, A. dealbata (which resembles A. mearnsii) and A. decurrens, both of which were probably introduced by mistake.

Occurrence: All three wattles – but in our area, A. mearnsii, the black wattle in particular - are aggressive invaders of grassland, indigenous bush, roadsides and in the Waterberg, especially, watercourses, although A. decurrens is less common. They seriously threaten local biodiversity.

Why they are a problem: These alien invasive species cause the crowding out and eventual elimination of indigenous species. Like eucalypts and poplars, they lead to the choking and drying up of watercourses; and in dense stands, can represent severe fire hazards. A. mearnsii is ranked top of the list of the World’s Worst Invasive Species.

Elimination / Control Methods: Long-term control of wattles is difficult, because they coppice readily and produce large numbers of seeds that can remain dormant for decades. The seeds are efficiently distributed by water and their germination is stimulated by fire. The species are amenable to physical and herbicidal control, but their readiness to re-grow and the propensity for seedlings to germinate once exposed to sunlight necessitates repeated attention and herbicide application. Plants should not be felled or burnt without immediate folllow-up with herbicides. The most successful approach involves a combination of mechanical and chemical attack, accompanied by sustained management.

Numerous herbicides have been registered for application to Acacia sp: for A. mearnsii alone, almost 60 branded products have been listed, too many to list below. Most are based on one of the following active ingredients:

Aminopyralid/triclopyr (various formulations): A. mearnsii

*Bromacil 500g/l SC: A. mearnsii, A. dealbata

*Bromacil/tebuthiuron 250/250 g/l SC: A. mearnsii, A. dealbata

Clopyralid/triclopyr 90/270 g/l SL: A. mearnsii

Fluroxypyr (various formulations): A. mearnsii

Glyphosate (various formulations): A. mearnsii, (A. dealbata)

Imazapyr 100 g/l SL: A. mearnsii

Picloram 240 g/l SL: A. dealbata, A. mearnsii

*Tebuthiuron 500 g/l SC: A. mearnsii

Triclopyr (various formulations): A. dealbata, A. mearnsii, A. decurrens

Consult your local herbicide stockist to obtain information about the most suitable branded product registered and available for your application. See also Van Zyl (2012).

*NB: herbicides containing bromacil or tebuthiuron must be applied with extreme caution, preferably only under the supervision of a herbicide specialist. Both agents are soil sterilants and can damage surrounding woody vegetation for many years after application.

Al herbicides should be applied early in the growing season. Note that all herbicides should be used when freshly mixed (do not leave the solution overnight).

NB: Follow carefully the instructions provided on herbicide label. Many herbicides can be toxic to other plants and or game and livestock if used inappropriately. (Mis-use of herbicides is also a criminal offence in terms of Act No. 36 of 1947).

 

References:

 

ARC-LNR Weeds & Invasive Plants website: www.agis.agric.za/wip

ARC-LNR SAPIA News No.8, July 2008; No.28, April 2013: ARC – Plant Protection Research Institute, Pretoria. www.arc.agric.za

Bromilow, Clive (2010): Problem Plants and Alien Weeds of South Africa. Briza. Pretoria.

Schmidt, Ernst, Mervyn Lotter & Warren McCleland (2007): Trees and Shrubs of Mpumalanga and Kruger National Park (2nd Edition). Jacana, Johannesburg.

Henderson, Lesley (2001): Alien Weeds & Invasive Plants. Agricultural Research Council (ARC), Pretoria.

Van Zyl, Kathy, (compiler) (2005): Control of Unwanted Plants. Xact Information, Pretoria.

Van Zyl, Kathy, (compiler) (2012): Problem Plant Control Compendium. AVCASA, Midrand This email address is being protected from spambots. You need JavaScript enabled to view it.

Special thanks to Dr Gerhard Verdoorn of Griffon Poison Information Centre, to Mr Ferdie Jordaan of Arysta Lifescience and to Ms Lesley Henderson of ARC for their invaluable advice and guidance. Their enthusiastic support for this voluntary project is greatly appreciated.

Just when you thought it was safe to go into the mountains again...

And it's true: our pristine, Biosphere-protected plateau is being invaded, mainly from the south, by a determined force of ruthless exploitative aliens from other lands or their allies from elsewhere in the country.

The Plant Protection Research Institute at the Agriculture Research Council in Pretoria has a very useful website (www.arc.agric.za) and issues very practical newsletters. They've been informing us about Lantana for quite a while "are you listening?"

If you have visited Vaalwater over the last two months, you have no doubt seen how prevalent Pompom weed is in the town and how fast it is spreading outwards into agricultural land.