The State of the World's Plants report 2017

1,730 new plant species discovered, including foods of the future

Kew’s second annual State of the Worlds Plants report, involving 128 scientists from 12 countries, reveals why some plants are more vulnerable than others to global threats such as climate change, disease, or pests, and presents data never seen before on patterns affecting plants in different regions.  This latest data also helps peel back a layer on how plants are relevant and valuable to all aspects of our lives.

  • Climate change – new evidence shows which plants have the ability to cope with change 
  • Medicinal plants – first time that 28,187 species recorded with a medicinal use 
  • Plant health – $540bn/yr cost to agriculture if invasive pests & pathogens aren’t controlled 
  • Wildfires – 340 million hectares of the earth’s vegetative surface burns annually (more than the size of India)

Among the 1,730 exciting plant discoveries revealed from the past year are five new species of Manihot from Brazil (relatives include cassava, manioc and tapioca). These species have the potential to develop the Manioc crop by diversifying it, allowing it to grow in drier climates than currently, and by providing defences against viruses which are reducing yields in some areas of the world.  There were also discoveries of seven new species of Aspalathus (Redbush), known for the South African rooibos tea and even a new parsnip species named in Turkey.  For the medical world, nine new species of the climbing vine genus Mucuna, used in the treatment of Parkinson’s disease, were found and named across South East Asia and South/ Central America. 

Gardeners will celebrate the discoveries of well-known plant species which offer the potential of new flower colours, new scents, longer flowering times, and different habitats to those already known in cultivation including 29 new species of Begonia, found mainly in the forests of Malaysia. 

Prof. Kathy Willis, director of science, RBG Kew says: 

“It’s an exciting time to be drilling into data on the plant world.  Plants are the foundation of the world’s ecosystems and hold the potential to tackle some of our most pressing issues, as we try to strike a delicate balance between our needs and those of the natural world. 

"We’ve tried to make sure that this year’s State of the World’s Plants report goes beyond the numbers to look at the natural capital of plants - how they are relevant and valuable to all aspects of our lives. From the technological advances allowing us to unravel the mysteries of plants to the detailed study of their characteristics - molecular to morphological - we are able to get a better picture than ever before of what we have that is valuable and what is most vulnerable.  I hope this will enable us to have a global conversation about what we need to protect and conserve.” 

Climate Change 

Professor Willis led the team which authored the chapter on climate change that looks at the winners and losers in the plant world under a changing climate. They reveal that plants with thicker leaves and bark, more efficient water use strategies, deeper roots and higher wood density are better able to cope with future climate change. These include increases in drought, fires, temperature and CO2. Deeper roots are found to be better able to withstand drought as are trees with high wood density.  Thicker leaves and taller grasses appear to do better in higher temperatures but conversely shorter trees do better overall. Plants that possess a combination of these traits will be the winners according to these findings.  

“It’s a different way of thinking, to look across biomes and examine which traits plants already possess that allow some to better tolerate the cocktail of climate change that will impact our ecosystems. The interesting fact to emerge is that the suite of ‘beneficial’ traits are, on the whole, the same the world over and are as true in a temperate forest as in a desert.” 

This can help to inform land use decisions like encouraging farmers to leave long rooted grasses on drought prone lands instead of removing them in favour of short rooted crops like wheat. When this happened in the US in the 1930’s the famous Dust Bowl storms ensued with disastrous ecological consequences.

Medicinal Plants 

The report also reveals that at least 28,187 plant species are currently recorded as being of medicinal use and that is probably a very conservative figure. Critically, it also asks why fewer than 16% (4,478) of the species used in plant-based medicines are cited in medicinal regulatory publications, and reveals that there are currently 15 alternative names for each medicinal species, causing confusion and risk in the sector.  The report suggest how this can be streamlined and improved in databases like Kew’s Medicinal Plant Names Service (MNPS

Her Excellency, Dr Gurib-Fakim, President of the Republic of Mauritius, who will be speaking at the Kew Symposium on the report on May 26th says; 

“This important report draws attention to issues like conservation, as well as how effectively regulation can be achieved through more precise use of scientific plant names and greater awareness of the many alternative synonyms in use.  Many of the 28.000+ species with medicinal potential have given modern medicine some very important leads yet few are actually listed officially because of ambiguous labelling.”

Plant Health 

The report also looks at the big issues facing plant health globally with a focus on the methods being used to control the spread of pests and pathogens. It calculates that $540bn/yr is the potential cost to world agriculture if the spread of invasive pests and pathogens is not stopped. The main reason for the scale of the problem is the increase in trade and travel due to globalisation which has contributed to the spread of pests and pathogens around the world. Trade in live plants is especially dangerous and the report recognises the need for stricter biosecurity measures.  The report lists the top 20 pests known and the efforts to control them.   Maize in Africa is being decimated by the Armyworm leading to starvation as well as rising food prices worldwide. The American ash species pathogen, emerald ash borer EAB, could cost the US over $300bn according to the research.


The report reveals that each year around 340 million hectares of the Earth's surface burns which is more than the size of India.  Kew’s Sarah Wyse, who co-authored the chapter in this report, has been doing work on plant flammability traits and reveals her findings.  A lot of fire research focuses on the broad scale effects of fire such as changing climate. However, society can't hope to make fire management decisions without information about the effects of changes in landscape flammability resulting from changes in plant composition.  A fire resilient landscape in the future would require land managers to consider avoiding planting large monocultures of highly flammable species - as has happened in Chile.  Instead, the report states that things like 'natural fire breaks' consisting of less flammable species should be encouraged, so if fires do occur, they are more likely to only affect smaller areas. 

Other headlines in this year’s report include

  • The number of plants with assembled whole genomes now stands at 225 and has risen by over 60% the last year alone. The report highlights information on how new technology is helping to speed up the discovery and classification of plants that are providing important sign posts to the next food crops, the effectiveness of conservation policies and actions in protecting some of the most important plant species globally.  For example, the sequence for one of the most widely used herbal medicines Chinese liquorice was revealed in 2017.
  • In the world of crops, rice registered the largest increase in the numbers sequenced but there remains much to be done.  When added to the information being gathered on the wild relatives of crops like rice, wheat, peanuts, potatoes, tomatoes, soybean, sweet potato and others, we have a growing picture of what we need to do to sustain our growing global population in a warming world. Even hops and grapes used in beer and wine have been studied this way to shed light on taste and quality as well as to increase yields in the longer term.
  • The country focus of this year’s report is Madagascar, the 4th largest island on earth and the only country where Kew has a permanent presence outside of the UK.  The report looked at the data available on the island using new analytical tools and perspectives. It concludes that 83% of Madagascar’s 11,138 native species of vascular plant occur nowhere else on earth and the size of its flora is equal to that of Uganda, Kenya & Tanzania combined.  The world's 4th largest island is home to five unique plant families and three times as many palm species as continental Africa. Madagascar has some spectacular unique palms - Tahina spectabilis, the giant suicide palm (known from) / found in just 2 localities. But the majority of Malagasy palms are the result of massive speciation in a single genus Dypsis into many habitats – hence why 83% of Madagascan species are endemic. 

Dr. Tianjanahary Randriamboavonjy, KMCC Communities Team Leader at the RBG Kew office in Madagascar (who will be attending the press launch and speaking at the report’s Symposium on May 25-26th) says: 

“Madagascar is known for its high level of endemism of plants and animals, but the diversity within Madagascar creates a huge challenge for conservation. Every fragment of remaining forest might contain new and undescribed species so we should re-evaluate our strategy to protect everything that is left. A report like this allows us to do this on the best scientific evidence available and with the participation of local people so we hope it will be heeded and lead to action.”

  • Plant conservation policy is also put under the microscope in this year’s report.  As a result of CoP17 an additional 304 species have been added to over 31,517 plant species currently listed on the CITES Appendices - lists of species afforded different levels or types of protection from over-exploitation. It reveals that there are many individual orchid species that are as threatened as the White Rhino, like Asian slipper orchids and many of Madagascar’s orchids.  Also trade in rare species shows no signs of abating. CITES legal plant trade into the EU in 2014 was worth US$286million with 2,320 plant taxa imported. The Illegal trade within the EU in wild species was estimated to be worth between €8-20 billion annually (EU 2016). The report demonstrates some of the ’Biodiversity Blunders’ that people commit when travelling around the world in a graphic image listing some of the cacti, herbal medicines, wood and food supplements that are illegal to move without certification.
  • 6,075 vascular plant species are now documented as invasive.  The report reveals that 44% of studies on the control of invasive plants in natural ecosystems examine the use of chemical methods.  The choice of control method currently appears to depend on the plant form i.e. whether it’s herbaceous or woody, but the report suggests that not enough is being done to understand what is actually most effective for a particular plant in a particular place and time. The report suggests that in many cases we are ‘fighting a complex  battle’, using the example of tree controls from South Africa and the trade-offs between a tree that is an invasive on one hand, and an important provider of fuel and food to local communities on the other.
  • New research reveals that there is only 53% congruence between Important Plant Areas (IPAs) and Important Bird and Biodiversity Areas (IBAs) across Europe and Mediterranean region.  This tells us that if we want to effectively prioritise conservation efforts, then a range of organism groups (e.g. birds, plants, butterflies etc.) need to be studied, as different sites are often of importance for different groups (i.e. we can't rely on animal-focussed conservation to protect our plant diversity). The chapter also reveals the most important sites for plants in Europe’s Mediterranean region are currently facing threats but, as many of these are at least partially protected by law, there is an opportunity to better manage these sites for their plants.
  • Extinction risk is examined in more depth this year from the perspective of which plant traits help predict their fate,  concluding the epiphytes and late bloomers may be more vulnerable to extinction than other plants.  It argues that reliable predictors of extinction risk are needed to improve conservation planning.  This is the first review on this scale that examines the evidence for those traits that might influence extinction risk in plants.


State of the World’s Plants Symposium, at Kew Gardens, London, 25 & 26th May, 2017

In conjunction with the publication of the cutting-edge annual report, scientists and policymakers will gather at Kew for the second international State of the World's Plants Symposium.  The two-day event is a platform to discuss issues raised in the report and to engage the scientific community, policymakers and public alike.  The symposium will be based around six themed sessions, each comprising talks from invited experts followed by a panel Q&A to discuss emerging issues.  View the full programme  

Chelsea Flower Show - 23-27th May, 2017 

A bold display created by the Royal Botanic Gardens, Kew in the Discovery Zone at this year’s Chelsea Flower show takes visitors on a global journey, highlighting the simple but often overlooked truth that all our lives depend on plants, and their future is in our hands. Themed around Kew’s pioneering State of the World’s Plants scientific report released in May, the display features exciting new plant discoveries, highlights from the biodiversity hotspot of Madagascar and plants capable of withstanding extreme environments in this climate-threatened world.   This is the first time that scientific data gathered by RBG Kew and its partners has been presented in this way to the public, and it hopes to spark a lifelong interest in the vital role that plants play in securing the future of the planet.  Three themes will be displayed in the exhibit: 

  1. Exciting New Plant Discoveries and conservation successes, including rare and endangered species, such as a critically endangered pitcher plant and the rarest and smallest waterlily in the world, Nymphaea thermarum 
  2. Madagascar – a country focus on important and fascinating plants from this biodiversity hotspot. 
  3. Plants in extremes – plants which live in extreme environments. Knowledge of plant evolution, resilience and distribution patterns is important to predicting future climatic and land use changes. 

Notes for editors 

The report will be publicly available from May 18th on the State of the World’s Plants website 

To find out more and to access the press gallery or request B-roll footage from the field (South Africa and Madagascar) please contact the Royal Botanic Gardens, Kew Press Office on 020 8332 5607 or email 

Royal Botanic Gardens, Kew

The Royal Botanic Gardens, Kew is a world famous scientific organisation, internationally respected for its outstanding collections as well as its scientific expertise in plant diversity, conservation and sustainable development in the UK and around the world. Kew Gardens is a major international and a top London visitor attraction. Kew’s 132 hectares of landscaped gardens, and Kew’s country estate, Wakehurst, attract over 1.5 million visits every year.