Invasive Alien Plants in South Africa Lesley Henderson KEY TO SYMBOLS LEGAL STATUS PE Prince Edward Isles only NEMBA category 1a: Requiring immediate compulsory control NEMBA category1b: throughout South Africa/in part of South Africa Must be controlled or eradicated where possible NEMBA category 2: throughout South Africa/in part of South Africa Allowed only in specified areas under controlled conditions NEMBA category 3: throughout South Africa/in part of South Africa Must be controlled within riparian areas; no further cultivation allowed INVASIVE STATUS T; Pt Transformer; Potential transformer S; E; R Special effect weed; Emerging weed; Ruderal and agrestal BIOLOGICAL CONTROL Effective biological control agents available; control complete Biological control agents available; control substantial Biological conrol agents available; control negligible Biological control agents available; control not determined or under evaluation Degree of biological control after Klein (2011) and updated 2018 Complete: no other control measures are needed to reduce the weed to acceptable levels, at least in areas where the agents have been established Substantial: other methods are needed to reduce the weed to acceptable levels, but less effort is required (e.g. less frequent herbicide application or less herbicide needed per unit area) Negligible: in spite of damage inflicted by the agents, control of the weed remains entirely reliant on the implementation of the other control measures Not determined: either the release of the agents has been too recent for the meaningful evaluation, or the programme has not been evaluated POTENTIAL THREAT OR IMPACT Biodiversity Water resources Fire Soil erosion Agriculture Forestry Human and animal health Tourism, recreation PLANT PROTECTION RESEARCH INSTITUTE HANDBOOK NO 21 INVASIVE ALIEN PLANTS IN SOUTH AFRICA by Lesley Henderson A complete guide to restricted invasive alien plants in South Africa, including another 40 taxa invasive in that region 1 INVASIVE ALIEN PLANTS IN SOUTH AFRICA by Lesley Henderson Copyright © 2020 Agricultural Research Council. All rights reserved. Permission is granted to Department of Environment, Forestry and Fisheries of South Africa to reproduce this publication or any part thereof for non-profit purposes and with full acknowledgement to the author and publisher. ISBN: 978-0-620-86146-5 Artists: Major Contributors Marietjie Steyn Wilma Roux Sandie Burrows Gill Condy Rita Weber Photographers: Major Contributors Lesley Henderson Geoff Nichols Design and layout: Mac Image Printing and binding: Novus Print Sponsor: Department of Environment, Forestry and Fisheries of South Africa: Natural Resources Management Programmes (DEFF: NRMP) 2 CONTENTS FOREWORD ............................................................................................................... 4 INTRODUCTION ......................................................................................................... 5 ACKNOWLEDGEMENTS ........................................................................................... 7 IMPACTS OF INVASIVE SPECIES ............................................................................... 9 INVASIVE STATUS .................................................................................................... 14 CONTROL METHODS .............................................................................................. 16 GUIDE TO IDENTIFICATION OF THE SPECIES ....................................................... 18 Example page ........................................................................................................... 18 Symbols used ............................................................................................................ 19 Grasses, Reeds and Grass-like Plants ........................................................................ 20 Aquatic and Wetland Plants ...................................................................................... 36 Marine Plants ............................................................................................................. 54 Herbs ......................................................................................................................... 56 Climbers and Scramblers ......................................................................................... 110 Trees and Shrubs: succulent .................................................................................... 134 Trees and Shrubs: woody ........................................................................................ 166 RESTRICTED SPECIES AND NEM:BA ..................................................................... 306 NATIONAL LISTS OF INVASIVE PLANT SPECIES ................................................... 310 BIOLOGICAL CONTROL AGENTS ......................................................................... 343 OTHER SOURCES OF INFORMATION .................................................................. 354 GLOSSARY ............................................................................................................. 358 INDEX OF BOTANICAL AND COMMON NAMES ................................................. 363 ABOUT THE AUTHOR ............................................................................................ 382 MAP OF SOUTH AFRICA AND PLACES ................................................................. 383 QUICK GUIDE (INSIDE BACK COVER) ............................................................... 384 3 FOREWORD The impacts of invasive plants cannot be over-emphasised: • They are the single biggest long-term threat to our water security. If our catchments are invaded by pines, wattles, hakea and other thirsty invasives, water security will collapse. • South Africa is the third-most species-rich country in the world. Invasive species are the single biggest threat to our exceptional biological diversity. • They exacerbate wild fires, many invasive species burning at ten-fold the intensity of the species that they displace. • They exacerbate erosion, siltation of rivers and dams, sedimentation and poor water quality, mudslides and flooding. For these reasons, South Africa has among the world’s most comprehensive programmes to address the problems of invasive species: • It is led by the Working for Water programme (now in its 25th year), through which about 50,000 people are employed to control invasive species. • South Africa is at the forefront of biological control research and application, finding the natural enemies of invasive plants, and ensuring that it is safe to release them in our country. • The Biosecurity Unit is strengthening our capacity to prevent the introduction of potentially invasive species; tackling emerging invasive species (before they become widespread), and enforcing our legislation on alien and invasive species. • The Value-Added Industries programme is utilizing invasive biomass for building materials, furniture and other products, freeing up budget to address priorities such as biological control, clearing of high-altitude areas and early detection of emerging species. As important as is this work, so much more needs to be done. South Africa will need the active engagement of its citizens, if it is to contain the threat of invasive species. It is each of us who must be aware of the risks of moving species to areas in which they do not occur, and to manage invasive species that are under our control. With so many invasive plant species already in our country, and a high risk of further invasions (including species that will become invasive as the climate changes), a first step is to be able to identify them. Lesley Henderson’s comprehensive revision of her seminal “Alien Weeds and Invasive Plants”, published in 2001, is greatly welcomed. This beautifully illustrated book, with its apt descriptions, is the product of decades of careful research and field work. It will also be published on-line, in an effort to reach as many key people as possible. It needs to be widely available, for we are all part of the problem – and part of the solution. May this book inspire more and more South Africans to take the necessary steps to contain invasive plants. We all owe Lesley Henderson a great deal, for her meticulous and dedicated work. Dr Guy Preston Deputy Director-General Department of Environment, Forestry and Fisheries 4 INTRODUCTION The main objective in producing this book is to enable members of the public and law enforcement officers to identify therestricted invasive alien plant species in South Africa covered by the “NATIONAL ENVIRONMENTAL MANAGEMENT: BIODIVERSITY ACT (NEM:BA) 2004” (Act No. 10 of Republic of South Africa 2004). The book includes a further 40 taxa invasive in this region, some of which have been proposed for listing in the regulations but require further assessment. The book also represents the culmination of the second phase of a mapping project, the Southern African Plant Invaders Atlas (SAPIA), which was started in 2006 and ended in 2016. The plants described in this book are alien or non-native species. All have been introduced into South Africa, either intentionally or unintentionally and with the exception of a few, have either escaped cultivation or become naturalised i.e. are capable of reproducing and spreading without the direct assistance of people. Some species are largely confined to places of severe human disturbance and are classified as ruderal weeds (of waste places) and agrestal weeds (of cultivated lands).