What are threatened cultivars and how are they tracked and conserved?
Fluctuating fashions, changes in the nursery trade, loss of specialist knowledge, environmental changes and new pests and diseases can all threaten the future of important cultivated plants. As part of our work combating these threats, Plant Heritage started the Threatened Plants Programme in 2009. Through the programme we track the locations and availability of garden cultivars and work out how rare or threatened they are.
Our research highlights the risks of plants disappearing forever. Of the 133,000 plants we have assessed, more than 1 in 3 are no longer reliably available commercially and for 1 in 6 we only have records of them growing in one or two locations.
How does it work?
The Threatened Plants Programme focuses on named cultivars known to have been grown in the UK or Ireland for at least 10 years. We combine data from the RHS Plant Finder (which shows availability of plants through hundreds of UK nurseries, 1987-present) with records from more than 2,000 locations, including the National Collections, Plant Exchange and Plant Guardian schemes and cultivar lists from botanic and historic gardens in the UK and Ireland.
If a cultivar has been grown or sold in the UK or Ireland more than ten years ago, but is no longer reliably found for sale through nurseries, it is considered Threatened in cultivation. Threatened plants may be Critical in cultivation (not found alive), Endangered in cultivation (grown in only one or two locations), or Vulnerable in cultivation (three or more sites).
We are adding new data all the time from different sources, and we share our data with partners like the RHS to help inform their conservation efforts. We consult with experts in the plant group, often a National Collection holder, who can provide more information to help us identify which plants are most in need of protection, and how best to approach this.
We are delighted when we find something is not as rare as we feared.
What can we do to help save rare plants?
Through the National Plant Collections, we and our members and volunteers are keeping nearly 100,000 plants safe, as a 'living library'. Through the Plant Guardian scheme, we find and keep track of rare and unusual plants, and through our annual free Plant Exchange for members we aim to get more of them back into circulation. With our network of local groups, we run regular events including specialist plant fairs, talks and workshops to share green skills and special plants.
Can you help us to protect more more plants, so we can all enjoy them in the future? Why not become a member, volunteer with us, or donate to help fund our plant conservation work?
Pelargonium 'Sussex Delight', Threatened:Critical, Listed between 1996-2012
“The wealth of information... is worth its weight in gold. I can put a value on some cultivars because I know how rare they are." Dan Luscombe, Curator
Information from the Threatened Plants Programme
Information from the Threatened Plants Programme helps collection holders prioritise their sourcing and propagation. It is also a unique resource for people searching for particular cultivars, such as new Collection Holders. We can often pinpoint who last had a particular cultivar, or contact a garden still growing it to see if they can supply propagating material.
Research is carried out by Plant Heritage staff and volunteers. We provide reports for Collection Holders, Groups and botanic gardens, supply information for the Plant Exchange and Plant Guardians, and help find plants that Collection Holders are looking for (see the desiderata page).
Endangered cultivars
The Threatened Plants Programme helps collection holders, head gardeners and plant enthusiasts manage their collections and identify rare plants. Plant Heritage is the only organisation researching threatened cultivated plants.
Read more about some of the work that the Threatened Plants Programme has been doing.
Primula 'Fife Yellow' Threatened:Endangered. Listed between 1997-2008
C Stone
What are the threats to our garden plants?
- Changing fashions
Changes in styles of planting and taste can cause groups of plants to go out of fashion. We don't want to lose the range of cultivars available for when they inevitably come back into fashion. - Changes to the plant sales trade
The requirement for plants to be of a specific size and in flower at the point of sale by garden centres and supermarkets can lead to a diminution of the range of plants grown in our gardens. We are also losing specialist plant nurseries who carry a much wider range of plants. - Climate change
Climate change over time will have a continuing effect on the range of cultivated plants available to the UK.
- Pests and pathogens
Due to the nature of modern trade and travel there is an increasing risk of new pests and diseases being introduced to the UK. Recent examples of these include box blight, ash dieback, and agapanthus gall midge. - Loss of propagation or cultivation skills
A lack of horticultural skills, particularly in propagation, is causing a loss in the availability of specialist cultivated plants.
Our partners
