Yet another example of a pretty plant that was introduced as a garden plant and has now become a serious menace. Like many invasive plants in Africa, this one comes from South America. Most invasive plants are either fom Australia or South America because billions of years ago, these continents were part of the same landmass. Although they are separate now, they share the same underlying geology and the soil composition is similar to what a particular plant needs. Being in the same latitudes in the same Hemisphere also makes weather conditions similar and so plants in a new ecosystem which lacks the predators and controls of the native environment really thrive and outcompete local plants and destroy fragile ecosystems.
Pompom weed is a particular threat because it also conducts chemical warfare against other plants: its roots secrete enzymes that inhibit the growth of other plants nearby. It is also unpalatable to grazing animals so it can cause huge losses to farmers if it takes over grazing areas.
So far, I have seen only one plant in the area and I will remove it but there are likely to be many more in time
