The Pink and Purple Problem

Landowners are alarmed by the spread of pink and purple flowers in the veld and wetlands. And they are confused about what to do.

What are these plants? Why are they a problem? And what should be done to stop the spread?

The Pink and Purple Problem

Everyone is noticing the pink fluffy flowers spreading. Alongside that, in many places is a purple flower of similar height.

The pompom came first (top left, first picture on mobile). The verbena has taken hold and is as serious (right). Both plants flower in summer, die down in winter and re-emerge after the first rain. They are perennials, meaning the plant from last season is the same plant which emerges in this season – alongside all the hundreds of plants which have grown from seed.

Do we HAVE to do something about it?

Yes. Look at what happens when pompom dominates in the veld…

The variety of natural vegetation is forced out, and the invasive plants take over. The loss of diversity in the veld has implications for ALL lifeforms – fewer varieties of insects, birds, small mammals… Remember the food chain from your school days? The loss of any link in that chain has repercussions throughout.

Good for something?

Fields of pink flowers must be good for something – right? What about being a great food source for bees?

Perhaps. Most specialists agree that it is mono-culture causing the decline in bee populations. Invaders take over, and create fields of one dominant plant – just as the farmers of single crops do!
We sacrifice biodiversity and habitat when invaders proliferate, so yes, there is grave concern for bees. It seems imperative to halt the invasion by pompom and verbena!

But we should not be irresponsible with treatment either. When using the herbicide on a plant that is already in flower, REMOVE THE FLOWERS. Not just for the protection of bees, but also to reduce the number of seeds floating in the wind.
The BEST solution all round is to use herbicide WELL BEFORE FLOWERING commences. No problem to insects and cheaper for you.

A fallen or cut flower still forms seeds. Drop the cut flowers into a bag, never the veld. Tie that bag really tight and keep the cut flowers out of the wind.
The herbicide hits the flowers quickly. Within a day or two, the flower stems are drooping and less attractive to all insects. Small buds shrivel and crumble when touched.

What’s the hurry?

According to one landowner who sent us a picture of dense Pompoms, it took only 2 years to spread over his entire property.

The more invaders present, the higher the cost and effort.
Invaders, by definition, spread rapidly. Pompom and verbena are especially vigorous in:
– disturbed soil,
– degraded veld,
– overgrazed veld or
– places where water gathers, even for a short time.

One way to stall infestation is to have a healthy veld, free of rubble or disturbance, and to monitor and control grazing.

Ideally, there must be good vegetation cover and a rich variety of plants and grasses.

Financial drain

The economic implications of a tardy and uncoordinated response are significant: each successive untreated season adds exponentially to the cost to clear. The costs peak when the invaders dominate. The veld will need to be rehabilitated to restore its health, certainly rested from grazing for several seasons.
I have heard landowners say, “We work and work, and the pompom gets no less”. If you do the same thing every year, and the situation gets worse, you need to change what you are doing. You may have been very effective in dealing with the SPECIFIC plant; it may be dead. But this is the problem: If you have not done more to prevent re-seeding, expect at least the same number of plants again next year – or, more likely, a significant increase. If you have sprayed late, and seeds have fallen, the problem grows.

Coordinate your efforts

If you have cleared your property well and in good time but your neighbour has been negligent, you can anticipate another flush of pink and purple next season.

Action triedThe problemThe Solution
Cutting off the flowersWell, that is all you are doing – cutting off a flower only prevents THAT flower from seeding. If you cut while the plant is healthy and growing, you have stimulated it to produce more flowers.Only cut the flower after you have applied herbicide.
Better yet, apply herbicide BEFORE the flowers appear. You will save time and effort.
Digging it outYou must dig out EVERY scrap of the plant – or the same plant will just appear again, perhaps even more than one if you have left bits of root behind. If you have VERY FEW pompom, mechanical removal is an option. Do it carefully, digging deep and wide around the plant. DESTROY the whole plant.
TIP: Walk into your veld and count the pompom. If you tire counting the pompom, there are too many to remove in this manner. Work out how long it will take to remove the pompom you have counted and ask yourself if you have that amount of time before the flowers turn to seed. If no, get out the herbicide.
Burning the veldPompom and verbena are just like our veld plants – adapted to survive fire. Their rhizomes store enough energy to kick-start the growth after a fire. Burn only in these circumstances: Your veld is moribund (thick with old, matted material). You have the permission of the Department of Agriculture. You have enough appropriate fire fighting equipment and people on hand to prevent the fire spreading. The first spring rain of more than 15mm has fallen. Once burned, wait until the pompom has 4 or more leaves, and then apply herbicide. It will be very easy to spot in the open veld.
Using herbicide other than those registered for the purpose (i.e. cheaper herbicide such as Roundup)You spray the plant with great care, and it seems to be dying. Only after weeks it has not died “properly”. So, you dig it up, or you apply some more herbicide…spending more time and more money on the same (rapidly ageing towards seeding) plant.The herbicides that are registered have been proven to be effective. They cost more, and they get the job done.
We have tested several products, each has pros and cons.
There is one in a fine powder form that needs constant agitation. Unless you are prepared to constantly stop and stir, or shake, avoid it.
There are granules that take longer to drop out of suspension but will still need agitation.
Herbicides that come in liquid form are easier to use. We use Plenum as it has a shorter half-life than its predecessor, Access. Both are from ECO Guard (www.ecoguard.co.za). Both presently cost a little more than R1 per liter in the sprayer.

Effect of cutting flowers

Cutting the flowers at the wrong time is ineffectual and wasteful.

Here are case examples:
The typical central stalk is cut (circle) and 6 new stems and flowers grow quickly. This photograph was taken where the landowner employed six people to work end-to-end cutting flowers. Before they were half-way, the veld where they had started had turned PINKER than before!

This photograph above indicates where stems were cut (see circles). Within days new stems had formed. Beyond the plants with the small buds, the more mature flowers on un-cut plants.
Landowners might buy themselves time by cutting flowers but as the only effort to control invaders, it fails.

Rule of thumb: what takes one day to spray takes three days to cut and bag.

ACKNOWLEDGEMENT: This is an extract from an article that was written in 2014 by the late Mercia Komen who inspired the creation of the Crocodile River Reserve.

One of the 10 Worst Weeds in the World – Lantana Camara (Verbenaceae)

Lantana is one of the worst weeds in the world, a category 1b species in South Africa in terms of the Alien and Invasive Species Regulations (AIS), National Environmental Management: Biodiversity Act (Act No 10 of 2004).

Yes, they may be shrubs with the prettiest flowers, but grow into huge bushes and are a real problem in the CRR and surrounding areas.

Land occupiers are legally obliged to control it, or to remove and destroy it if possible. No trade or planting is allowed.

It comprises a complex of vigorous, prolific, man-made hybrids, bred in Europe from unrecorded parents from Central and South America, and spread all over the world as a hardy, ornamental shrub, with multi-coloured flowers. Dispersed by fruit-eating birds, it establishes along fence lines and under trees, where it out-competes indigenous plants and forms impenetrable, prickly thickets that reduce natural pasturage, productivity of cattle farming, access to water supplies and tree plantations, biodiversity, and land values.

Lantana camara is a perennial, erect sprawling or scandent, shrub which typically grows to around 2 metres (6+1⁄2 feet) tall and form dense thickets in a variety of environments. Under the right conditions, it can scramble up into trees and can grow to 6 m (20 ft) tall.

The leaves are broadly ovate, opposite, and simple and have a strong odour when crushed.
L. camara has small tubular-shaped flowers, which each have four petals and are arranged in clusters in terminal areas stems. Flowers come in many different colours, including red, yellow, white, pink, and orange, which differ depending on location in inflorescences, age, and maturity. The flower has a tutti fructi smell with a peppery undertone. After pollination occurs, the colour of the flowers changes (typically from yellow to orangish, pinkish, or reddish); this is believed to be a signal to pollinators that the pre-change colour contains a reward as well as being sexually viable, thus increasing pollination efficiency. In frost-free climates the plant can bloom all year round, especially when the soil is moist.

Lantana camara complex (L. camera has several hybrids) is very prevalent in the CRR and it’s surrounding areas. It has been listed as a threat to our biodiversity, water resources, agriculture and as a fire hazard. The entire plant is poisonous to humans and other mammals, especially the unripe fruit.

Effective management of invasive L. camara in the long term will require a reduction in activities that create degraded habitats. Maintaining functioning (healthy) ecosystems is key to preventing invasive species from establishing themselves and out-competing native fauna and flora.

Insects and other biocontrol agents have been implemented with varying degrees of success in an attempt to control L. camara. It was the first weed ever subjected to biological control; however, none of the programs have been fully successful.

The lack of success using biological control in this case is most likely due to the many hybrid forms of L. camara, as well as its large genetic diversity which makes it difficult for the control agents to target all plants effectively.

Mechanical control of L. camara involves physically removing the plants. Physical removal can be effective but is labour-intensive and expensive,] therefore removal is usually only appropriate in small areas or at the early stages of an infestation.

Another method of mechanical control is to use fire treatment, followed by revegetation with native species.

Using herbicides to manage L. camara is very effective. The most effective way of chemically treating plant species is to cut back the shrub and poison the main stem with a mix of Gladiator, Actipron and Eco Blue Dye. The entire plant can be dug out but if the bush is large this can be quite difficult as they are very hardy and prickly. Gloves must be worn when eradicating this invasive alien.