A pompom pandemic
PINK FLOWER: GREENLANDS IN DANGER WITH RAPID GROWTH OF WEEDS
The plant is covered in rough and coarse bristly hairs
‘It has spread in Gauteng, Limpopo, North West, Mpumalanga, KwaZulu-Natal.’
The pink pompom pandemic is posing a danger for South African greenlands and doubling at an alarming rate. Alekzandra Mari Szewczuk, a PhD candidate at the School of Animal, Plant, and Environmental Sciences at Wits University, said it seems as though the pompoms have doubled this year due to the amount of rain this summer.
“As South Africa has just come out of a drought, it is likely that pompom may not have flowered as prolifically during the drought years. However, due to its nature of seed dispersal and the size of viable seed banks, it is probable that the pompom infestations are now growing alarmingly fast.”
The pompom weed is a perennial thistle-like plant with striking pink flower heads that originates from South America, with native ranges in Argentina, Uruguay and Panama.
“It produces annual stems in spring from September to October from a dense tuber-like rootstock and the erected stems can grow up to 1.5m high,” she said.
“The plant is covered in rough and coarse bristly hairs. The leaves are arranged in a cluster at the base and scattered up the length of the stem. The striking pink flower heads are arranged in closely packed groups towards the ends of the stems.”
Szewczuk said a single plant had several flower heads and a single flower head could produce hundreds of tiny seeds similar to a dandelion.
“Pompoms flower in summer between December and April in large infestations that creates a spectacular pink carpet,” she said.
She said various control options include physical control – uprooting, mowing, or cutting off flower heads before they seed – chemical control such as herbicides, fire and biological control, which is the use of natural enemies or biocontrol agents from the pompom’s native range.
“The mechanical methods are limited by ineffectiveness and time constraints and often stimulate further growth, the chemical methods are not only costly but pose adverse threats in environmentally sensitive areas, while burning can remove the pompom stems and kill seeds, but it also stimulates regrowth from the rootstock,” she said.
Szewczuk said no one was sure when the pompom was introduced to South Africa.
“But it was recorded here in the early 1960s. So far, it has spread to large parts of Gauteng, as well as parts of the Limpopo, North West and Mpumalanga. There also seem to be some populations in northern KwaZulu-Natal.”
Marion Mengell, who worked as a conservationist at the Friends of Nylsvlei in Limpopo, described the flower as the pompom pandemic.
“The story goes the pompom flower was used in the flower exhibition at the Voortrekker Monument years ago and escaped and spread to the Groen Kloof area,” she said.
Mengell said the weed which usually blooms during late summer, from December to February, has invaded the Rietvlei nature reserve and Faerie Glen nature reserve.
Wendy Carstens, Conservation manager at Melville Koppies, said grasslands were all in danger with exponential growth recently favoured by rainy season.
Carstens said in small areas like Melville Koppies, they tackle them immediately by bagging the flower heads and then carefully digging out the roots.
“We sometimes also use herbicide on the leaves and stems once we have deflowered them. This is only possible in a small area that is monitored and conserved regularly,” she said.