THIS FEATURE IS FROM VELD & FLORA MARCH ISSUE 108(1), PAGES 40-43

#PROTECT

​​Sinister succulents in South Africa 

APRIL 11, 2022 | Written by Reshnee Lalla. Photographs by KZN DIRECTORATE ON BIODIVERSITY EVIDENCE/SANBI

These three succulents are new on SA’s watchlist because they seem potentially invasive. They are Mauritius hemp (above), Brazilian prickly pear cactus (top left) and spiral ginger (top right). Photos: KZN Directorate on Biodiversity Evidence/SANBI

Do your bit to protect SA’s indigenous plants by helping spot this new wave of menacing succulents. 

BRAMBLE, LANTANA, BUGWEED . . .  

this Terrible Trio are some of the best-known – and least-loved – plants in South Africa. They are all invasive alien plants which have established themselves in such big populations across the country that it is sadly no longer feasible to eradicate them.

Instead, we need to try to protect our surviving indigenous plants by containing them – and also by keeping ahead of the next wave of invaders.

Here we highlight the next generation’s Threatening Threesome. All three succulents highlighted here are on the watchlist at the Directorate of Biodiversity Evidence as emerging invasive alien plants.

They already show some signs of being invasive – growing in areas where they were not deliberately planted, such as along roadsides and streams. They do not yet qualify as established invasive alien plants like lantana and bugweed because their populations are relatively small and they are not distributed in too many areas.

MAURITIUS HEMP HOTSPOTS

We started tracking Mauritius hemp (Furcraea foetida) in 2010 and began control programmes from 2014. Current KZN hotspot areas with large populations of this suspect succulent are:

• South coast (Ugu municipality: towns such as Margate and Port Shepstone)
• Durban and surrounds (eThekwini municipality) inland through towns such as Westville, Kloof, Cato Ridge and Hammarsdale to Pietermaritzburg (Umgungundlovu municipality)
• North coast (iLembe municipality) and on into Tongaat, Stanger, Shakaskraal and Empangeni

Mauritius hemp has also now unfortunately been recorded in four other provinces – the Eastern Cape, Western Cape, Mpumalanga and Limpopo. We are carrying out a formal risk analysis to guide us on whether it is still possible to eradicate it from South Africa. In the meantime, it is vital to continue controlling known Mauritius hemp populations to try to prevent its spread into new areas.

EYES WIDE OPEN

We were first alerted to another suspicious unknown plant by a member of the public who had seen it on a farm near Hluhluwe in northern KZN in mid- 2019. It was the Brazilian prickly pear cactus (Brasiliopuntia brasiliensis). Our staff also discovered more of these plants on a neighbouring property and we have tracked population sizes and extent. One population has also been reported in Limpopo. Another suspect that we were first alerted to by a concerned member of the public was spiral ginger (Costus afer). In 2019, we were warned of a small population of KZN south coast plants near Port Shepstone. The only other populations that we know about are near Westville.

Any input that you can provide will help us better understand whether or not spiral ginger is a risk in South Africa and how it typically behaves. It could be much more widespread than we  know because its striking flower and eye-catching leaf arrangement make it likely that this plant is being cultivated in private gardens and/or even sold in nurseries.